fix(ci): use soul.c-first link with --allow-multiple-definition

Linux elb generates individual .c files; soul.c does not contain merged
imports (unlike macOS elb which produces a unified file). Re-link all
dist/*.c manually with soul.c listed first so its real main() wins, and
--allow-multiple-definition to silence GNU ld's duplicate symbol errors.
All duplicates are identical (same El source, different compile units).

.gitea/workflows/ci.yaml

@@ -109,21 +109,26 @@ jobs:
           ELC=/opt/el/dist/platform/elc
           RUNTIME=/opt/el/runtime
 
-          # Compile all El modules to C (may fail at link on Linux: the El compiler
-          # inlines imported modules into each module's .c file, producing duplicate
-          # symbol definitions that GNU ld rejects as errors. macOS ld accepts them
-          # silently. We ignore the link failure and re-link manually below.)
+          # Compile all El modules to C.
+          # This step will fail at link on Linux: the El compiler inlines imported
+          # modules into each module's .c file, producing duplicate strong symbol
+          # definitions. GNU ld rejects these; macOS ld accepts them silently.
+          # We capture the link failure and re-link manually below.
           $ELB --elc=$ELC --runtime=$RUNTIME/el_runtime.c || true
 
-          # soul.c is a fully self-contained merged file — every function from every
-          # imported module is inlined into it. Link only soul.c against el_runtime.c;
-          # this avoids all duplicate-symbol conflicts from the individual module files.
+          # Re-link with soul.c listed first so its real main() (from the cgi block)
+          # wins over the stub main()s generated in every other module.
+          # --allow-multiple-definition tells GNU ld to pick the first definition
+          # for each duplicate symbol — safe here because all duplicates are identical
+          # (same El source compiled independently into multiple .c files).
           mkdir -p dist
+          OTHER_C=$(ls dist/*.c | grep -v '/soul\.c$' | sort | tr '\n' ' ')
           cc -O2 -DHAVE_CURL \
             -I$RUNTIME \
-            dist/soul.c \
+            dist/soul.c $OTHER_C \
             $RUNTIME/el_runtime.c \
             -lssl -lcrypto -lcurl -lpthread -lm \
+            -Wl,--allow-multiple-definition \
             -o dist/neuron
 
           ls -lh dist/neuron