aco: Work around MSVC restrict in c99_compat.h

Future LLVM header leads to __declspec(__restrict), which is invalid.
Just undefine the restrict macro to keep __declspec(restrict).

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13505>

src/amd/compiler/aco_print_asm.cpp

@@ -25,6 +25,9 @@
 #include "aco_ir.h"
 
 #ifdef LLVM_AVAILABLE
+#if defined(_MSC_VER) && defined(restrict)
+#undef restrict
+#endif
 #include "llvm/ac_llvm_util.h"
 
 #include "llvm-c/Disassembler.h"