Hello,

If I compile this example:
#include <stdio.h>
#include <float.h>

int main() {
printf("%g", FLT_EPSILON);
return 0;
}

With:
i686-w64-mingw32-gcc -isystem /usr/i686-w64-mingw32/include -o main.c.obj -c main.c

I get this error:
main.c:6:16: error: ‘FLT_EPSILON’ undeclared (first use in this function)
printf("%g", FLT_EPSILON);

The '-isystem /usr/i686-w64-mingw32/include' part was added by the qt cmake use file of mingw-w64-testsuite package, and I cut it down after the compilation of the test for mingw-w64-bullet failed.

It can be reproduced from this CMakeLists.txt:
cmake_minimum_required ( VERSION 2.8 )
project ( mingw-test C CXX )
find_package ( Qt4 REQUIRED QtCore)
include ( ${QT_USE_FILE} )
add_executable(main main.c)

Actually I don't know if it's a bug of gcc, qt, or cmake!

Can you provide feedback on this ?