ci: compile elc.c from El repo source for linux/amd64 support

The El repo only has a darwin arm64 elc binary. The v1.2.1 linux
binary predates native HTML template syntax. Compile elc.c (the
committed C source of the El compiler) on linux/amd64 in CI to
get a native binary that supports the new syntax.

.gitea/workflows/dev.yaml

@@ -34,18 +34,36 @@ jobs:
         with:
           fetch-depth: 2
 
-      - name: Set up El SDK from source
+      - name: Set up El SDK (build linux elc from repo C source)
         env:
           CHECKOUT_TOKEN: ${{ secrets.CHECKOUT_TOKEN }}
         run: |
           set -euo pipefail
+
+          # Ensure build tools are available (ci-base may not have gcc)
+          if ! command -v cc >/dev/null 2>&1; then
+            apt-get update -qq
+            apt-get install -y -qq gcc libcurl4-openssl-dev libssl-dev
+          fi
+
           DEST="${{ github.workspace }}/../foundation-el"
-          # Clone El repo — native HTML template syntax requires latest elc,
-          # not the v1.2.1 release binary (282KB vs 486KB, different feature set).
+
+          # Clone El repo for source files, runtime, and JS runtime
           git -c "http.extraheader=Authorization: token ${CHECKOUT_TOKEN}" clone \
             --depth=1 \
             "https://git.neuralplatform.ai/neuron-technologies/el.git" \
             "$DEST"
+
+          # Compile elc.c (committed C source of the El compiler) for linux/amd64.
+          # The darwin arm64 binary at lang/dist/platform/elc can't run on linux.
+          # elc.c is the same compiler source but in C — compile it natively here.
+          cc -std=c11 -O2 \
+             -I "$DEST/lang/el-compiler/runtime" \
+             -lcurl -lpthread \
+             -o "$DEST/lang/dist/platform/elc" \
+             "$DEST/lang/dist/platform/elc.c" \
+             "$DEST/lang/el-compiler/runtime/el_runtime.c"
+
           chmod +x "$DEST/lang/dist/platform/elc"
           echo "EL_HOME=$DEST/lang" >> "$GITHUB_ENV"