ci: Disable Werror on wrapped subprojects

Enabling Werror on our code is good, but it's less good on external
projects. Some of the Rust subprojects are now failing due to warnings
exposed by the newer Rust toolchain in Fedora, which we don't care about.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33137>

.gitlab-ci/meson/build.sh

@@ -15,6 +15,13 @@ comma_separated() {
   echo "$*"
 }
 
+no_werror() {
+  # shellcheck disable=SC2048
+  for i in $*; do
+    echo "-D${i}:werror=false "
+  done
+}
+
 CROSS_FILE=/cross_file-"$CROSS".txt
 
 export PATH=$PATH:$PWD/.gitlab-ci/build
@@ -132,9 +139,12 @@ else
     MAX_LD=${FDO_CI_CONCURRENT:-4}
 fi
 
+# these are built as Meson subprojects; we want to use Meson's
+# --force-fallback-for to ensure that we build the subprojects from their wrap
+# files, and we also want to disable Werror on those, since we do not control
+# these projects and making them warning-free is not our goal.
 # shellcheck disable=2206
-force_fallback_for=(
-  # FIXME: explain what these are needed for
+meson_subprojects=(
   perfetto
   syn
   paste
@@ -150,10 +160,12 @@ force_fallback_for=(
 section_switch meson-configure "meson: configure"
 
 rm -rf _build
+# shellcheck disable=SC2046
 meson setup _build \
       --native-file=native.file \
       --wrap-mode=nofallback \
-      --force-fallback-for "$(comma_separated "${force_fallback_for[@]}")" \
+      --force-fallback-for "$(comma_separated "${meson_subprojects[@]}")" \
+      $(no_werror "${meson_subprojects[@]}") \
       ${CROSS+--cross "$CROSS_FILE"} \
       -D prefix=$PWD/install \
       -D libdir=lib \