fix(ci): simplify musl-g++ wrapper to only disable FORTIFY_SOURCE

The musl-gcc.specs approach strips all system include paths via
-nostdinc, which removes C++ standard library headers and breaks
std::atomic detection in z3's cmake build.

Simpler approach: the only glibc-specific symbols z3 was pulling in
were __printf_chk and similar __*_chk functions generated by
_FORTIFY_SOURCE hardening.  Disabling _FORTIFY_SOURCE makes g++ emit
standard printf/memcpy/etc. calls that musl provides, while keeping
all C++ headers intact.

Author: johntmyers

.github/workflows/release-dev.yml

@@ -206,10 +206,13 @@ jobs:
         run: |
           set -euo pipefail
           # musl-tools ships musl-gcc (C wrapper) but not a C++ equivalent.
-          # z3's bundled cmake build needs a C++ compiler that targets musl.
-          # Extract the specs path from musl-gcc and create a parallel g++ wrapper.
-          SPECS=$(sed -n 's/.*-specs "\([^"]*\)".*/\1/p' "$(which musl-gcc)")
-          printf '#!/bin/sh\nexec g++ "$@" -specs "%s"\n' "$SPECS" > /usr/local/bin/musl-g++
+          # z3's cmake build needs a C++ compiler for the musl target.
+          # Using the musl-gcc.specs with g++ breaks C++ headers (-nostdinc
+          # strips them).  Instead, disable _FORTIFY_SOURCE which is the only
+          # source of glibc-specific symbols (__printf_chk, __memcpy_chk, etc.)
+          # that musl doesn't provide.  Standard C/C++ symbols are fine — musl
+          # implements them all.
+          printf '#!/bin/sh\nexec g++ -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0 "$@"\n' > /usr/local/bin/musl-g++
           chmod +x /usr/local/bin/musl-g++
 
       - name: Add Rust musl target

.github/workflows/release-tag.yml

@@ -227,8 +227,7 @@ jobs:
       - name: Create musl-g++ wrapper
         run: |
           set -euo pipefail
-          SPECS=$(sed -n 's/.*-specs "\([^"]*\)".*/\1/p' "$(which musl-gcc)")
-          printf '#!/bin/sh\nexec g++ "$@" -specs "%s"\n' "$SPECS" > /usr/local/bin/musl-g++
+          printf '#!/bin/sh\nexec g++ -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0 "$@"\n' > /usr/local/bin/musl-g++
           chmod +x /usr/local/bin/musl-g++
 
       - name: Add Rust musl target