Within gthr-vxworks.h, we prevent C++ errors from missing declarations in some system headers by prepending their inclusion with a #pragma GCC diagnostic ignored "-Wstrict-prototypes" But Wstrict-prototypes is internally registered as valid for C/ObjC only, not C++, and this trick in turn triggers a Wpragma warning with -Wsystem-headers. This change just arranges to ignore the secondary warning locally. We have been using this for a while with gcc-11 based toolchains, where the only effect was the intended disappearance of a test failure observed on g++.dg/warn/Wstringop-overflow-6.C. Sanity checked with a build + basic testing with a gcc-12 compiler, then a mainline build for arm-vxworks7r2. Cheers Olivier 2021-02-03 Olivier Hainque * config/gthr-vxworks.h: Prevent Wpragma warning for the pragma diagnostics on Wstrict-prototypes.