util/disk_cache: support caches for multiple architectures
util/disk_cache: support caches for multiple architectures

Previously we were deleting the entire cache if a user switched
between 32 and 64 bit applications.

V2: make the check more generic, it should now work with any
platform we are likely to support.

V3: Use suggestion from Emil to make even more generic/fix issue
with __ILP32__ not being declared on gcc for regular 32-bit builds.

Tested-by: Grazvydas Ignotas <eac34e836c3bc120048c86fead6dd0257a872a9e@gmail.com>
Tested-by: Dieter Nützel <902ea9f4f1fbe947e8e8c77ca59f21dfca158b7e@nuetzel-hh.de>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler