GHA CI: enable run-time checks in C++ library

Those have minimal impact on run-time:
https://www.gnu.org/software/libc/manual/html_node/Source-Fortification.html
https://bugs.launchpad.net/kicad/+bug/1838448/comments/40

PR #19608.

.github/workflows/ci_macos.yaml

@@ -87,7 +87,7 @@ jobs:
 
       - name: Build qBittorrent
         run: |
-          CXXFLAGS="$CXXFLAGS -Wno-gnu-zero-variadic-macro-arguments -Werror -Wno-error=deprecated-declarations" \
+          CXXFLAGS="$CXXFLAGS -Werror -Wno-error=deprecated-declarations" \
           LDFLAGS="$LDFLAGS -gz" \
           cmake \
             -B build \