fix(ci): fall back to ci-base:latest when ci-base:dev doesn't exist yet

The BASE build arg was hardcoded to ci-base:dev even when the pull fell
back to :latest. Docker then tried to resolve ci-base:dev from the
registry during the build and failed.

Capture which tag was actually pulled and use that as BASE.

.gitea/workflows/ci-dev.yaml

@@ -252,4 +252,52 @@ jobs:
             --source=el-compiler/runtime/el_runtime.js
 
           echo "Published El SDK version=${VERSION} to foundation-dev"
+          # Keep key alive for the ci-base rebuild step below
+          # (deleted in that step after docker push)
+
+      - name: Rebuild ci-base with fresh El SDK (dev)
+        # Patches ci-base:dev in-place: pulls the existing image (which has all
+        # system deps — Node, Go, gcloud, Docker CLI, etc.) and overlays the freshly
+        # built El SDK on top. Keeps the full ci-base rebuild fast and incremental.
+        if: github.event_name == 'push'
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+        run: |
+          set -euo pipefail
+          CI_BASE="us-central1-docker.pkg.dev/neuron-785695/neuron-ci/ci-base"
+          SHA="${GITHUB_SHA:0:8}"
+
+          echo "${GCP_SA_KEY}" > /tmp/gcp-key.json
+          gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
+          gcloud config set project neuron-785695
+          gcloud auth configure-docker us-central1-docker.pkg.dev --quiet
+
+          # Pull existing ci-base:dev (or fall back to :latest on first run)
+          BASE_TAG="dev"
+          docker pull "${CI_BASE}:dev" || { docker pull "${CI_BASE}:latest" && BASE_TAG="latest"; }
+
+          # Inline Dockerfile — only replaces the El SDK layer
+          cat > /tmp/Dockerfile.ci-base-patch << 'EOF'
+          ARG BASE
+          FROM ${BASE}
+          COPY dist/platform/elc                 /opt/el/dist/platform/elc
+          COPY dist/bin/elb                       /opt/el/dist/bin/elb
+          COPY el-compiler/runtime/el_runtime.c  /opt/el/el-compiler/runtime/el_runtime.c
+          COPY el-compiler/runtime/el_runtime.h  /opt/el/el-compiler/runtime/el_runtime.h
+          COPY el-compiler/runtime/el_runtime.js /opt/el/el-compiler/runtime/el_runtime.js
+          RUN chmod +x /opt/el/dist/platform/elc /opt/el/dist/bin/elb
+          EOF
+
+          docker build \
+            --build-arg BASE="${CI_BASE}:${BASE_TAG}" \
+            --build-arg BUILDKIT_INLINE_CACHE=1 \
+            -f /tmp/Dockerfile.ci-base-patch \
+            -t "${CI_BASE}:dev" \
+            -t "${CI_BASE}:dev-${SHA}" \
+            .
+
+          docker push "${CI_BASE}:dev"
+          docker push "${CI_BASE}:dev-${SHA}"
+
+          echo "ci-base rebuilt: ${CI_BASE}:dev (${SHA})"
           rm -f /tmp/gcp-key.json

.gitea/workflows/ci-stage.yaml

@@ -246,4 +246,51 @@ jobs:
             --source=el-compiler/runtime/el_runtime.h
 
           echo "Published El SDK version=${VERSION} to foundation-stage"
+          # Keep key alive for the ci-base rebuild step below
+          # (deleted in that step after docker push)
+
+      - name: Rebuild ci-base with fresh El SDK (stage)
+        # Patches ci-base:stage in-place: pulls the existing image (which has all
+        # system deps — Node, Go, gcloud, Docker CLI, etc.) and overlays the freshly
+        # built El SDK on top. Keeps the full ci-base rebuild fast and incremental.
+        if: github.event_name == 'push'
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+        run: |
+          set -euo pipefail
+          CI_BASE="us-central1-docker.pkg.dev/neuron-785695/neuron-ci/ci-base"
+          SHA="${GITHUB_SHA:0:8}"
+
+          echo "${GCP_SA_KEY}" > /tmp/gcp-key.json
+          gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
+          gcloud config set project neuron-785695
+          gcloud auth configure-docker us-central1-docker.pkg.dev --quiet
+
+          # Pull existing ci-base:stage (system deps stay cached in the base layer)
+          docker pull "${CI_BASE}:stage" || docker pull "${CI_BASE}:latest"
+
+          # Inline Dockerfile — only replaces the El SDK layer
+          cat > /tmp/Dockerfile.ci-base-patch << 'EOF'
+          ARG BASE
+          FROM ${BASE}
+          COPY dist/platform/elc                 /opt/el/dist/platform/elc
+          COPY dist/bin/elb                       /opt/el/dist/bin/elb
+          COPY el-compiler/runtime/el_runtime.c  /opt/el/el-compiler/runtime/el_runtime.c
+          COPY el-compiler/runtime/el_runtime.h  /opt/el/el-compiler/runtime/el_runtime.h
+          COPY el-compiler/runtime/el_runtime.js /opt/el/el-compiler/runtime/el_runtime.js
+          RUN chmod +x /opt/el/dist/platform/elc /opt/el/dist/bin/elb
+          EOF
+
+          docker build \
+            --build-arg BASE="${CI_BASE}:stage" \
+            --build-arg BUILDKIT_INLINE_CACHE=1 \
+            -f /tmp/Dockerfile.ci-base-patch \
+            -t "${CI_BASE}:stage" \
+            -t "${CI_BASE}:stage-${SHA}" \
+            .
+
+          docker push "${CI_BASE}:stage"
+          docker push "${CI_BASE}:stage-${SHA}"
+
+          echo "ci-base rebuilt: ${CI_BASE}:stage (${SHA})"
           rm -f /tmp/gcp-key.json

lang/el-compiler/runtime/el_runtime.c

@@ -42,6 +42,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <pthread.h>
+#include <sys/resource.h>  /* getrusage — memory guard */
 #ifdef HAVE_CURL
 #include <curl/curl.h>
 #endif
@@ -2241,6 +2242,43 @@ el_val_t url_decode(el_val_t sv) {
     return el_wrap_str(out);
 }
 
+/* ── html_raw ────────────────────────────────────────────────────────────────
+ * Identity passthrough for raw HTML template interpolation.
+ * El's {raw(expr)} compiles to html_raw(expr) — the value is output as-is
+ * without any escaping. The caller is responsible for safety.
+ */
+el_val_t html_raw(el_val_t s) {
+    return s;
+}
+
+/* ── html_escape ─────────────────────────────────────────────────────────────
+ * Escape < > " ' & for safe HTML text interpolation.
+ * El's {expr} in HTML templates compiles to html_escape(expr).
+ */
+el_val_t html_escape(el_val_t sv) {
+    const char* src = EL_CSTR(sv);
+    if (!src) return EL_STR("");
+    size_t len = strlen(src);
+    /* Worst case: every byte → 6 chars (&quot;) */
+    char* out = (char*)malloc(len * 6 + 1);
+    if (!out) return sv;
+    el_arena_track(out);
+    char* p = out;
+    for (size_t i = 0; i < len; i++) {
+        unsigned char c = (unsigned char)src[i];
+        switch (c) {
+            case '&':  memcpy(p, "&amp;",  5); p += 5; break;
+            case '<':  memcpy(p, "&lt;",   4); p += 4; break;
+            case '>':  memcpy(p, "&gt;",   4); p += 4; break;
+            case '"':  memcpy(p, "&quot;", 6); p += 6; break;
+            case '\'': memcpy(p, "&#39;",  5); p += 5; break;
+            default:   *p++ = (char)c;          break;
+        }
+    }
+    *p = '\0';
+    return el_wrap_str(out);
+}
+
 /* ── HTML allowlist sanitizer ────────────────────────────────────────────────
  * el_html_sanitize(input, allowlist_json)
  *
@@ -5674,6 +5712,50 @@ el_val_t getpid_now(void) {
     return (el_val_t)getpid();
 }
 
+/* el_mem_check — self-terminating memory guard for long-running compiler runs.
+ *
+ * Call this periodically (e.g. after each function compiled) to detect runaway
+ * memory growth before the OS OOM-killer fires. Reads the limit from the env
+ * var ELC_MAX_MEM_MB (default 512 MB). If resident set size exceeds the limit,
+ * prints a diagnostic to stderr and exits with code 1 so the caller (elb or a
+ * CI script) can handle the failure gracefully instead of having the whole
+ * machine go down.
+ *
+ * Platform notes:
+ *   macOS  — ru_maxrss is in bytes.
+ *   Linux  — ru_maxrss is in kilobytes.
+ * We normalise to MB before comparing.
+ *
+ * Returns 0 always (the only non-return path is the exit() branch).
+ */
+el_val_t el_mem_check(void) {
+    /* Read limit from env; default 512 MB. */
+    long limit_mb = 512;
+    const char *env_val = getenv("ELC_MAX_MEM_MB");
+    if (env_val && *env_val) {
+        long v = atol(env_val);
+        if (v > 0) limit_mb = v;
+    }
+
+    struct rusage ru;
+    if (getrusage(RUSAGE_SELF, &ru) != 0) return 0; /* can't read — skip check */
+
+    long rss_mb;
+#if defined(__APPLE__) || defined(__MACH__)
+    /* macOS: ru_maxrss is bytes */
+    rss_mb = (long)(ru.ru_maxrss / (1024L * 1024L));
+#else
+    /* Linux: ru_maxrss is kilobytes */
+    rss_mb = (long)(ru.ru_maxrss / 1024L);
+#endif
+
+    if (rss_mb >= limit_mb) {
+        fprintf(stderr, "elc: memory limit exceeded (%ldMB), aborting\n", limit_mb);
+        exit(1);
+    }
+    return 0;
+}
+
 /* ── args() — command-line argument access ──────────────────────────────────
  * Compiled El programs call args() to get a list of CLI arguments.
  * Call el_runtime_init_args(argc, argv) at the start of C main() to populate.

lang/el-compiler/runtime/el_runtime.h

@@ -227,6 +227,8 @@ el_val_t  url_decode(el_val_t s);   /* '+' → space, %XX → byte  */
  *     {"p":[],"a":["href","title"],"strong":[],...}
  * where each value is the array of attribute names allowed for that tag. */
 el_val_t  el_html_sanitize(el_val_t input_html, el_val_t allowlist_json);
+el_val_t  html_raw(el_val_t s);
+el_val_t  html_escape(el_val_t s);
 
 /* ── Filesystem ──────────────────────────────────────────────────────────── */
 
@@ -531,6 +533,12 @@ el_val_t  parse_int(el_val_t s, el_val_t default_val);
 el_val_t  exit_program(el_val_t code);
 el_val_t  getpid_now(void);
 
+/* Self-terminating memory guard. Reads ELC_MAX_MEM_MB (default 512) and
+ * exits with code 1 if resident memory exceeds the limit. Call periodically
+ * during long compilation loops (e.g. after each function is compiled).
+ * Returns 0 when memory is within bounds.                                   */
+el_val_t  el_mem_check(void);
+
 /* ── CGI identity ─────────────────────────────────────────────────────────────
  * Called at the start of main() in CGI programs (those with a `cgi {}` block).
  * Records the program's DHARMA identity before any other code executes.      */

lang/el-compiler/src/codegen.el

@@ -3730,6 +3730,7 @@ fn codegen_streaming(tokens: [Any], sigs: [Map<String, Any>], source: String) ->
                             cg_fn(stmt)
                             el_release(stmt)
                             el_arena_pop(fn_arena_mark)
+                            el_mem_check()
                         }
                     } else {
                         if is_top_level_decl(stmt) {

lang/el-compiler/src/compiler.el

@@ -287,6 +287,9 @@ fn type_node_to_el(t: Map<String, Any>) -> String {
 
 // emit_header — write a .elh file from parsed statements.
 // Scans for FnDef nodes and emits 'extern fn' declarations.
+// NOTE: This function requires the full AST. Prefer emit_header_from_sigs
+// for the --emit-header path — it works from a token-level scan without
+// building expression ASTs, avoiding OOM on large files.
 fn emit_header(stmts: [Map<String, Any>], hdr_path: String) -> Void {
     let n: Int = native_list_len(stmts)
     let i = 0
@@ -325,6 +328,32 @@ fn emit_header(stmts: [Map<String, Any>], hdr_path: String) -> Void {
     let ok: Bool = fs_write(hdr_path, content)
 }
 
+// emit_header_from_sigs — write a .elh file from pre-scanned El signatures.
+// Uses the output of scan_fn_sigs_el() — no full AST required.
+// Peak memory is O(tokens) rather than O(whole-program AST), which prevents
+// OOM on large files with HTML template bodies or deep BinOp chains.
+fn emit_header_from_sigs(sigs: [Map<String, Any>], hdr_path: String) -> Void {
+    let n: Int = native_list_len(sigs)
+    let i: Int = 0
+    let parts: [String] = native_list_empty()
+    let parts = native_list_append(parts, "// auto-generated by elc --emit-header — do not edit\n")
+    while i < n {
+        let sig = native_list_get(sigs, i)
+        let kind: String = sig["kind"]
+        if str_eq(kind, "fn") {
+            let name: String = sig["name"]
+            let params_el: String = sig["params_el"]
+            let ret_el: String = sig["ret_el"]
+            if str_eq(ret_el, "") { let ret_el = "Any" }
+            let line: String = "extern fn " + name + "(" + params_el + ") -> " + ret_el
+            let parts = native_list_append(parts, line + "\n")
+        }
+        let i = i + 1
+    }
+    let content: String = str_join(parts, "")
+    let ok: Bool = fs_write(hdr_path, content)
+}
+
 // ── Import resolution ────────────────────────────────────────────────────────
 //
 // elc supports two forms of import:
@@ -536,16 +565,20 @@ fn main() -> Void {
 
     let src_path: String = native_list_get(positional, 0)
 
-    // When --emit-header is requested, parse the source file directly
-    // (without inlining imports) and write out a .elh file alongside the .c.
+    // When --emit-header is requested, lex the source file and do a
+    // token-level signature scan (no full AST) to write a .elh file.
+    // This avoids OOM on large files with HTML template bodies or deep
+    // BinOp chains (e.g. checkout.el) — parse() builds O(whole-program AST)
+    // while scan_fn_sigs_el keeps peak memory at O(tokens).
     if do_emit_header {
+        el_mem_check()
         let raw_source: String = fs_read(src_path)
         let hdr_tokens: [Any] = lex(raw_source)
-        let hdr_stmts: [Map<String, Any>] = parse(hdr_tokens)
+        let hdr_sigs: [Map<String, Any>] = scan_fn_sigs_el(hdr_tokens)
         el_release(hdr_tokens)
         let hdr_path: String = str_slice(src_path, 0, str_len(src_path) - 3) + ".elh"
-        emit_header(hdr_stmts, hdr_path)
-        el_release(hdr_stmts)
+        emit_header_from_sigs(hdr_sigs, hdr_path)
+        el_release(hdr_sigs)
     }
 
     let source: String = resolve_imports(src_path)

lang/el-compiler/src/parser.el

@@ -2065,6 +2065,219 @@ fn skip_expr_to_stmt_boundary(tokens: [Any], pos: Int) -> Int {
     p
 }
 
+// scan_type_el — read a type annotation starting at pos and return its El
+// source representation as a string, plus the new position.
+// Returns { "el": String, "pos": Int }.
+// Handles: Ident, [Type], Map<K,V>, Type?, Type<T,...> (same shapes as skip_type).
+fn scan_type_el(tokens: [Any], pos: Int) -> Map<String, Any> {
+    let k: String = tok_kind(tokens, pos)
+    // Array type: [Type]
+    if str_eq(k, "LBracket") {
+        let p: Int = pos + 1
+        let inner = scan_type_el(tokens, p)
+        let inner_str: String = inner["el"]
+        let p = inner["pos"]
+        el_release(inner)
+        let p = expect(tokens, p, "RBracket")
+        return { "el": "[" + inner_str + "]", "pos": p }
+    }
+    // Named type (possibly generic or optional)
+    if str_eq(k, "Ident") {
+        let name: String = tok_value(tokens, pos)
+        let p: Int = pos + 1
+        let k2: String = tok_kind(tokens, p)
+        if str_eq(k2, "Lt") {
+            // Generic params: collect until matching >
+            let p = p + 1
+            let depth: Int = 1
+            let parts: [String] = native_list_empty()
+            let parts = native_list_append(parts, name + "<")
+            let running: Bool = true
+            while running {
+                let kk: String = tok_kind(tokens, p)
+                if str_eq(kk, "Eof") {
+                    let running = false
+                } else {
+                    if str_eq(kk, "Lt") {
+                        let depth = depth + 1
+                        let parts = native_list_append(parts, "<")
+                        let p = p + 1
+                    } else {
+                        if str_eq(kk, "Gt") {
+                            let depth = depth - 1
+                            let p = p + 1
+                            if depth <= 0 {
+                                let parts = native_list_append(parts, ">")
+                                let running = false
+                            } else {
+                                let parts = native_list_append(parts, ">")
+                            }
+                        } else {
+                            if str_eq(kk, "Comma") {
+                                let parts = native_list_append(parts, ", ")
+                                let p = p + 1
+                            } else {
+                                let parts = native_list_append(parts, tok_value(tokens, p))
+                                let p = p + 1
+                            }
+                        }
+                    }
+                }
+            }
+            let k3: String = tok_kind(tokens, p)
+            if str_eq(k3, "QuestionMark") { let p = p + 1 }
+            let result: String = str_join(parts, "")
+            el_release(parts)
+            return { "el": result, "pos": p }
+        }
+        // Optional marker
+        if str_eq(k2, "QuestionMark") {
+            return { "el": name + "?", "pos": p + 1 }
+        }
+        return { "el": name, "pos": p }
+    }
+    // Fallback: unknown token, treat as Any
+    { "el": "Any", "pos": pos + 1 }
+}
+
+// scan_params_el — scan a parameter list `(name: Type, ...)` starting at
+// position `pos` (which should point at LParen) and return the El parameter
+// declaration string (e.g. "a: String, b: Int") along with the new position.
+// Returns { "el": String, "pos": Int }.
+// Used by scan_fn_sigs_el for --emit-header without building full AST.
+fn scan_params_el(tokens: [Any], pos: Int) -> Map<String, Any> {
+    let p: Int = expect(tokens, pos, "LParen")
+    let parts: [String] = native_list_empty()
+    let going: Bool = true
+    while going {
+        let kk: String = tok_kind(tokens, p)
+        if str_eq(kk, "RParen") {
+            let going = false
+        } else {
+            if str_eq(kk, "Eof") {
+                let going = false
+            } else {
+                let pname: String = tok_value(tokens, p)
+                let p = p + 1
+                let p = expect(tokens, p, "Colon")
+                let tr = scan_type_el(tokens, p)
+                let ptype: String = tr["el"]
+                let p = tr["pos"]
+                el_release(tr)
+                let parts = native_list_append(parts, pname + ": " + ptype)
+                let k2: String = tok_kind(tokens, p)
+                if str_eq(k2, "Comma") {
+                    let p = p + 1
+                }
+            }
+        }
+    }
+    let p = expect(tokens, p, "RParen")
+    let el_str: String = str_join(parts, ", ")
+    el_release(parts)
+    { "el": el_str, "pos": p }
+}
+
+// scan_fn_sigs_el — lightweight token-level pre-scan for --emit-header.
+//
+// Like scan_fn_sigs but captures El-style type strings instead of C types.
+// Only records fn/extern_fn entries (header generation ignores lets/blocks).
+//
+// Descriptor shape:
+//   { "kind": "fn"|"extern_fn", "name": String,
+//     "params_el": String,   <- El param list, e.g. "a: String, b: Int"
+//     "ret_el": String }     <- El return type, e.g. "String" or "Void"
+//
+// Peak memory: O(tokens) with no expression AST allocation.
+fn scan_fn_sigs_el(tokens: [Any]) -> [Map<String, Any>] {
+    let total: Int = native_list_len(tokens) / 2
+    let sigs: [Map<String, Any>] = native_list_empty()
+    let pos: Int = 0
+    let going: Bool = true
+    while going {
+        if pos >= total {
+            let going = false
+        } else {
+            let k: String = tok_kind(tokens, pos)
+            if str_eq(k, "Eof") {
+                let going = false
+            } else {
+                // --- fn definition ---
+                if str_eq(k, "Fn") {
+                    let p: Int = pos + 1
+                    let name: String = tok_value(tokens, p)
+                    let p = p + 1
+                    let pr = scan_params_el(tokens, p)
+                    let params_el: String = pr["el"]
+                    let p = pr["pos"]
+                    el_release(pr)
+                    // read return type
+                    let ret_el: String = "Any"
+                    let k2: String = tok_kind(tokens, p)
+                    if str_eq(k2, "Arrow") {
+                        let p = p + 1
+                        let tr = scan_type_el(tokens, p)
+                        let ret_el = tr["el"]
+                        let p = tr["pos"]
+                        el_release(tr)
+                    }
+                    // skip body
+                    let k3: String = tok_kind(tokens, p)
+                    if str_eq(k3, "LBrace") {
+                        let p = skip_to_rbrace(tokens, p)
+                    }
+                    if !str_eq(name, "main") {
+                        let sigs = native_list_append(sigs, {
+                            "kind": "fn",
+                            "name": name,
+                            "params_el": params_el,
+                            "ret_el": ret_el
+                        })
+                    }
+                    let pos = p
+                } else {
+                // --- extern fn ---
+                if str_eq(k, "Extern") {
+                    let p: Int = pos + 1
+                    let k2: String = tok_kind(tokens, p)
+                    if str_eq(k2, "Fn") {
+                        let p = p + 1
+                        let name: String = tok_value(tokens, p)
+                        let p = p + 1
+                        let pr = scan_params_el(tokens, p)
+                        let params_el: String = pr["el"]
+                        let p = pr["pos"]
+                        el_release(pr)
+                        let ret_el: String = "Any"
+                        let k3: String = tok_kind(tokens, p)
+                        if str_eq(k3, "Arrow") {
+                            let p = p + 1
+                            let tr = scan_type_el(tokens, p)
+                            let ret_el = tr["el"]
+                            let p = tr["pos"]
+                            el_release(tr)
+                        }
+                        let sigs = native_list_append(sigs, {
+                            "kind": "extern_fn",
+                            "name": name,
+                            "params_el": params_el,
+                            "ret_el": ret_el
+                        })
+                        let pos = p
+                    } else {
+                        let pos = pos + 1
+                    }
+                } else {
+                    // Let, Cgi, Service, Import, Type, Enum, From — skip to boundary.
+                    let p: Int = pos + 1
+                    let p = skip_expr_to_stmt_boundary(tokens, p)
+                    let pos = p
+                }}}
+            }
+        }
+    sigs
+}
+
 // scan_params_c — scan a parameter list `(name: Type, ...)` starting at
 // position `pos` (which should point at LParen) and return the C parameter
 // declaration string along with the new position.

lang/elb.el

@@ -77,6 +77,33 @@ fn parse_manifest_entry(src: String) -> String {
     return ""
 }
 
+// parse_manifest_c_sources - collect all `c_source "path"` lines from the
+// build block.  Returns a flat list of path strings.
+fn parse_manifest_c_sources(src: String) -> [String] {
+    let result: [String] = native_list_empty()
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "c_source ") {
+            let after: String = str_slice(t, 9, str_len(t))
+            let trimmed: String = str_trim(after)
+            if str_starts_with(trimmed, "\"") {
+                let inner: String = str_slice(trimmed, 1, str_len(trimmed))
+                let q: Int = str_index_of(inner, "\"")
+                if q >= 0 {
+                    let path: String = str_slice(inner, 0, q)
+                    let result = native_list_append(result, path)
+                }
+            }
+        }
+        let i = i + 1
+    }
+    return result
+}
+
 fn parse_manifest_name(src: String) -> String {
     let lines: [String] = str_split(src, "\n")
     let n: Int = native_list_len(lines)
@@ -274,7 +301,11 @@ fn link_binary(c_files: [String], out_bin: String, runtime_path: String, out_dir
     // Detect clang vs gcc: -fbracket-depth is clang-only; silently ignored
     // if unsupported but gcc rejects it with an error.
     let bracket_flag: String = "$(cc --version 2>&1 | grep -q clang && printf -- '-fbracket-depth=1024' || true)"
-    let parts = native_list_append(parts, "cc -O2 " + bracket_flag + " -I " + dirname_of(runtime_path) + " -I " + out_dir)
+    // On macOS, OpenSSL is not on the default linker path. Detect homebrew
+    // prefix and add it if present (no-op on Linux where libssl is in /usr/lib).
+    let ossl_lib_flag: String = "$(brew --prefix openssl 2>/dev/null | xargs -I{} printf -- '-L{}/lib' 2>/dev/null || true)"
+    let ossl_inc_flag: String = "$(brew --prefix openssl 2>/dev/null | xargs -I{} printf -- '-I{}/include' 2>/dev/null || true)"
+    let parts = native_list_append(parts, "cc -O2 " + bracket_flag + " " + ossl_inc_flag + " -I " + dirname_of(runtime_path) + " -I " + out_dir)
     let i = 0
     while i < n {
         let f: String = native_list_get(c_files, i)
@@ -282,7 +313,7 @@ fn link_binary(c_files: [String], out_bin: String, runtime_path: String, out_dir
         let i = i + 1
     }
     let parts = native_list_append(parts, runtime_path)
-    let parts = native_list_append(parts, "-lcurl -lssl -lcrypto -lpthread -lm")
+    let parts = native_list_append(parts, ossl_lib_flag + " -lcurl -lssl -lcrypto -lpthread -lm")
     let parts = native_list_append(parts, "-o " + out_bin)
     let cmd: String = str_join(parts, " ")
     println("  link     " + out_bin)
@@ -315,6 +346,7 @@ fn main() -> Void {
 
     let pkg_name: String = parse_manifest_name(manifest_src)
     let entry: String    = parse_manifest_entry(manifest_src)
+    let extra_c: [String] = parse_manifest_c_sources(manifest_src)
     if str_eq(entry, "") {
         println("elb: manifest.el has no 'entry' declaration")
         exit(1)
@@ -393,6 +425,15 @@ fn main() -> Void {
         exit(1)
     }
 
+    // Append any extra C sources declared in the manifest (e.g. platform stubs)
+    let ei = 0
+    let en: Int = native_list_len(extra_c)
+    while ei < en {
+        let ec: String = native_list_get(extra_c, ei)
+        let c_files = native_list_append(c_files, ec)
+        let ei = ei + 1
+    }
+
     // Link
     let out_bin: String = out_dir + "/" + pkg_name
     let linked: Bool = link_binary(c_files, out_bin, runtime_path, out_dir, dry_run)