ref: 3a3e491a8bc624eb1c3b34e54ebee8d33942add2
parent: 0186d78da9e83103eb80b3814d4de8031f29232f
author: Ben Harris <bjh21@bjh21.me.uk>
date: Thu Feb 16 16:31:47 EST 2023
Enable -Wmissing-declarations in STRICT mode on GCC Clang's -Wmissing-declarations means something quite different, so we only enable it on GCC. This is slightly silly since Clang's -Wmissing-declarations is enabled by default, but it makes it clear that we know they're different.