ccache: implicit declaration of vdupq_n_s32

[chrstphrchvz (Christopher Chavez)]

ccache always tests for ARM NEON support regardless of whether building its bundled blake3 on Intel or Apple Silicon (see ​https://github.com/ccache/ccache/blob/v4.6.1/src/third_party/blake3/CMakeLists.txt#L110), and on Intel this leads to a warning about an implicit function declaration of vdupq_n_s32.

I’m aware that warnings for functions can be ignored with configure.checks.implicit_function_declaration.whitelist-append, but is there a preferred way of ignoring intrinsics only on non-ARM? Or, should ccache change how it checks for/enables NEON support?