Determining if the Q_WS_WIN exist failed with the following output:
Change Dir: /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/gmake" "cmTC_071d8/fast"
/usr/bin/gmake -f CMakeFiles/cmTC_071d8.dir/build.make CMakeFiles/cmTC_071d8.dir/build
gmake[1]: Entering directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_071d8.dir/CheckSymbolExists.cxx.o
/usr/bin/x86_64-pc-linux-gnu-g++  -I/usr/include/qt4   -DNDEBUG -O2 -pipe -march=native    -o CMakeFiles/cmTC_071d8.dir/CheckSymbolExists.cxx.o -c /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx: In function ‘int main(int, char**)’:
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: error: ‘Q_WS_WIN’ was not declared in this scope
   return ((int*)(&Q_WS_WIN))[argc];
                   ^~~~~~~~
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: note: suggested alternative: ‘Q_WS_X11’
   return ((int*)(&Q_WS_WIN))[argc];
                   ^~~~~~~~
                   Q_WS_X11
gmake[1]: *** [CMakeFiles/cmTC_071d8.dir/build.make:66: CMakeFiles/cmTC_071d8.dir/CheckSymbolExists.cxx.o] Error 1
gmake[1]: Leaving directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
gmake: *** [Makefile:126: cmTC_071d8/fast] Error 2

File /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:
/* */
#include <QtCore/qglobal.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef Q_WS_WIN
  return ((int*)(&Q_WS_WIN))[argc];
#else
  (void)argc;
  return 0;
#endif
}

Determining if the Q_WS_QWS exist failed with the following output:
Change Dir: /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/gmake" "cmTC_06c44/fast"
/usr/bin/gmake -f CMakeFiles/cmTC_06c44.dir/build.make CMakeFiles/cmTC_06c44.dir/build
gmake[1]: Entering directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_06c44.dir/CheckSymbolExists.cxx.o
/usr/bin/x86_64-pc-linux-gnu-g++  -I/usr/include/qt4   -DNDEBUG -O2 -pipe -march=native    -o CMakeFiles/cmTC_06c44.dir/CheckSymbolExists.cxx.o -c /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx: In function ‘int main(int, char**)’:
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: error: ‘Q_WS_QWS’ was not declared in this scope
   return ((int*)(&Q_WS_QWS))[argc];
                   ^~~~~~~~
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: note: suggested alternative: ‘Q_WS_X11’
   return ((int*)(&Q_WS_QWS))[argc];
                   ^~~~~~~~
                   Q_WS_X11
gmake[1]: *** [CMakeFiles/cmTC_06c44.dir/build.make:66: CMakeFiles/cmTC_06c44.dir/CheckSymbolExists.cxx.o] Error 1
gmake[1]: Leaving directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
gmake: *** [Makefile:126: cmTC_06c44/fast] Error 2

File /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:
/* */
#include <QtCore/qglobal.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef Q_WS_QWS
  return ((int*)(&Q_WS_QWS))[argc];
#else
  (void)argc;
  return 0;
#endif
}

Determining if the Q_WS_MAC exist failed with the following output:
Change Dir: /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/gmake" "cmTC_b84e1/fast"
/usr/bin/gmake -f CMakeFiles/cmTC_b84e1.dir/build.make CMakeFiles/cmTC_b84e1.dir/build
gmake[1]: Entering directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_b84e1.dir/CheckSymbolExists.cxx.o
/usr/bin/x86_64-pc-linux-gnu-g++  -I/usr/include/qt4   -DNDEBUG -O2 -pipe -march=native    -o CMakeFiles/cmTC_b84e1.dir/CheckSymbolExists.cxx.o -c /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx: In function ‘int main(int, char**)’:
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: error: ‘Q_WS_MAC’ was not declared in this scope
   return ((int*)(&Q_WS_MAC))[argc];
                   ^~~~~~~~
/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:8:19: note: suggested alternative: ‘Q_WS_X11’
   return ((int*)(&Q_WS_MAC))[argc];
                   ^~~~~~~~
                   Q_WS_X11
gmake[1]: *** [CMakeFiles/cmTC_b84e1.dir/build.make:66: CMakeFiles/cmTC_b84e1.dir/CheckSymbolExists.cxx.o] Error 1
gmake[1]: Leaving directory '/var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp'
gmake: *** [Makefile:126: cmTC_b84e1/fast] Error 2

File /var/tmp/portage/media-gfx/openmesh-7.1/work/openmesh-7.1_build/CMakeFiles/CMakeTmp/CheckSymbolExists.cxx:
/* */
#include <QtCore/qglobal.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef Q_WS_MAC
  return ((int*)(&Q_WS_MAC))[argc];
#else
  (void)argc;
  return 0;
#endif
}