meson,macos: fix BXF_EXE_FMT_MACH_O not being defined by configure
meson,macos: fix BXF_EXE_FMT_MACH_O not being defined by configure

Snaipe/BoxFort,Snaipe/BoxFort,diacritic/BoxFort,diacritic/BoxFort,Snaipe/BoxFort,diacritic/BoxFort,diacritic/BoxFort,Snaipe/BoxFort