compiler_gcc.h defined _rotl/_rotr/_rotl64/_rotr64 as macros before
mingw's <stdlib.h> got a chance to declare them as functions. Any
translation unit that did `#include "lib_common.h"` (which transitively
pulls in compiler_gcc.h) and later included <stdlib.h> — utils.c does
exactly this — would have the mingw function declarations textually
substituted by the macros, producing a syntax error.
Force <stdlib.h> in from compiler_gcc.h on mingw so the function
declarations are parsed before the macro names get shadowed. The
later #include in utils.c becomes a no-op via the header guard, and
call sites still resolve to the macros below (so the generated code
is unchanged on every other compiler/target).
This unblocks the Crafter.Build CI's x86_64-w64-mingw32 cross-compile,
which has been failing for a while when building Crafter.Asset →
gdeflate → libdeflate as a dep.
