macOS ARM: silence the 'redefining builtin macro' preprocessor warning

That was annoying.

Fixes: #558

Author: xavierleroy

configure

@@ -436,7 +436,7 @@ if test "$arch" = "aarch64"; then
         clinker="${toolprefix}cc"
         clinker_needs_no_pie=false
         cprepro="${toolprefix}cc"
-        cprepro_options="-arch arm64 -U__GNUC__ -U__clang__ -U__BLOCKS__ '-D__attribute__(x)=' '-D__asm(x)=' '-D_Nullable=' '-D_Nonnull=' '-D__DARWIN_OS_INLINE=static inline' -Wno-\\#warnings -E"
+        cprepro_options="-arch arm64 -U__GNUC__ -U__clang__ -U__BLOCKS__ '-D__attribute__(x)=' '-D__asm(x)=' '-D_Nullable=' '-D_Nonnull=' '-D__DARWIN_OS_INLINE=static inline' -Wno-\\#warnings -Wno-builtin-macro-redefined -E"
         libmath=""
         system="macos"
         pic_supported=true