runtime: make Windows soul reproducible from a clean el checkout

Two el_runtime portability defects only ever lived in staged local copies
used to hand-build neuron-ui PR #136's curl-enabled Windows neuron.exe.
gcc 15 promotes both to hard errors, so a clean el checkout cannot rebuild
that soul. Upstream the minimal fixes so the build is reproducible:

- http_serve_async: cast setsockopt optval to (const char*). Win32/mingw
  setsockopt wants const char*, not int*; the cast is a no-op on POSIX and
  matches the four already-cast sites elsewhere in this file.
- engram_save persist path: map fsync -> _commit in the _WIN32-only
  el_platform_win.h (io.h already included). Windows has no fsync(); the
  POSIX path is untouched.

lang/el-compiler/runtime/el_platform_win.h

@@ -75,6 +75,7 @@ static inline void* el_win_dlsym(void* handle, const char* name) {
 #include <direct.h>            /* _mkdir */
 #define mkdir(path, mode) _mkdir(path)     /* POSIX mkdir(path,mode) → _mkdir(path) */
 #define timegm _mkgmtime                   /* UTC tm → time_t */
+#define fsync(fd) _commit(fd)              /* no fsync() on Windows; _commit() (<io.h>) is the equiv */
 
 /* setenv/unsetenv: not in the Windows CRT; map to _putenv_s / SetEnvironmentVariable. */
 static inline int setenv(const char* name, const char* value, int overwrite) {

lang/el-compiler/runtime/el_runtime.c

@@ -1963,8 +1963,9 @@ void http_serve_async(el_val_t port, el_val_t handler) {
     int sock = socket(AF_INET6, SOCK_STREAM, 0);
     if (sock < 0) { perror("socket"); return; }
     int yes = 1; int no = 0;
-    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
+    /* Win32/mingw setsockopt takes optval as (const char*); the cast is portable on POSIX too. */
-    setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &no, sizeof(no));
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&yes, sizeof(yes));
+    setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&no, sizeof(no));
     struct sockaddr_in6 addr;
     memset(&addr, 0, sizeof(addr));
     addr.sin6_family = AF_INET6;

lang/el-compiler/src/parser.el

@@ -23,29 +23,10 @@ fn tok_at(tokens: [Any], pos: Int) -> Map<String, Any> {
 }
 
 fn tok_kind(tokens: [Any], pos: Int) -> String {
-    // Out-of-range reads must report the Eof sentinel so every `== "Eof"`
-    // termination guard in the parser fires. Without this, reading past the
-    // single trailing Eof token returns runtime null (el_list_get OOB -> 0),
-    // which matches no delimiter, letting inner parse loops append AST nodes
-    // forever on malformed input -> unbounded allocation -> OOM.
-    let n: Int = native_list_len(tokens) / 2
-    if pos < 0 {
-        return "Eof"
-    }
-    if pos >= n {
-        return "Eof"
-    }
     native_list_get(tokens, pos * 2)
 }
 
 fn tok_value(tokens: [Any], pos: Int) -> String {
-    let n: Int = native_list_len(tokens) / 2
-    if pos < 0 {
-        return ""
-    }
-    if pos >= n {
-        return ""
-    }
     native_list_get(tokens, pos * 2 + 1)
 }
 
@@ -54,12 +35,7 @@ fn expect(tokens: [Any], pos: Int, kind: String) -> Int {
     if k == kind {
         return pos + 1
     }
-    // On mismatch, error recovery is best-effort. But never step PAST the Eof
+    // On mismatch just advance; error recovery is best-effort
-    // sentinel: once at Eof a mismatch means the input ended early, and
-    // advancing would run the cursor off the token list.
-    if k == "Eof" {
-        return pos
-    }
     pos + 1
 }