SOURCES = main.cpp for (config, SIMD) { uc = $$upper($$config) DEFINES += QT_COMPILER_SUPPORTS_$${uc} add_cflags { cflags = QMAKE_CFLAGS_$${uc} !defined($$cflags, var): error("This compiler does not support $${uc}") QMAKE_CXXFLAGS += $$eval($$cflags) } }