Try FreeBSD workaround

Author: tautschnig

.github/workflows/bsd.yaml

@@ -49,7 +49,10 @@ jobs:
             gmake -C src -j2 CXX="ccache clang++"
             # gmake -C jbmc/src setup-submodules
             # gmake -C jbmc/src -j2 CXX="ccache clang++"
-            gmake -C unit "CXX=ccache clang++"
+            # https://github.com/catchorg/Catch2/issues/2910 is an issue
+            # specific to Clang/LLVM 19 (which is what FreeBSD 15 ships)
+            gmake -C unit "CXX=ccache clang++" \
+              CXXFLAGS="-Wall -pedantic -Werror -Wswitch-enum -Wno-deprecated-declarations -Wno-c++20-extensions"
             # gmake -C jbmc/unit "CXX=ccache clang++"
             echo "Print ccache stats"
             ccache -s