The QMAKE_COMPILER_DEFINES are used when running moc. In some cases, Qt
checks the __GNUC__ value to determine which version of GCC is being
used. In particular, the qtconcurrentfilter and qtconcurrentmap tests
fail to compile because moc ends up defining QT_NO_CONCURRENT_FILTER and
QT_NO_CONCURRENT_MAP since the condition __GNUC__ < 4 evaluates to true.
The Mac OS X development tools have not used gcc 3.x is a very long
time. The current version ships with llvm-gcc-4.2.1 and clang (which
also masquerades as gcc 4.2.1). Defining __GNUC__=4 makes sure that moc
preprocesses headers in the same way the compiler does.
Change-Id: Ie491d3f5b074fd1a509ffe6755f3308836817b6c
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
42ebe71775