SOURCES = avx512.cpp !defined(AVX512, "var"): error("You must set the AVX512 variable!") varname = QMAKE_CFLAGS_AVX512$$AVX512 value = $$eval($$varname) !defined($$varname, "var"): error("This compiler does not support AVX512") QMAKE_CXXFLAGS += $$value DEFINES += WANT_AVX512=$$AVX512 WANT_AVX512$$AVX512