Cmake/Mingw32: cmake command fails - testCCompiler.c not found - c++

Question

I have a problem while running cmake with a mingw32 custom compiler in a cygwin terminal.
I have already tried several approaches to fix my problem, until I got to the point where it only fails on finding testCCompiler.c from the directory CmakeTmp.
When I try to manually make the temporary files after cmake failed, the make command runs successfully. (Used --debug-trycompile to keep temporary files)
This is the output from the CMakeError.log file:
Determining if the C compiler works failed with the following output:
Change Dir: /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make.exe" "cmTC_5e0c4/fast"
/usr/bin/make -f CMakeFiles/cmTC_5e0c4.dir/build.make CMakeFiles/cmTC_5e0c4.dir/build
make[1]: Verzeichnis „/cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp“ wird betreten
Building C object CMakeFiles/cmTC_5e0c4.dir/testCCompiler.c.o
/opt/mingw32-1.6.0/bin/i686-w64-mingw32-gcc-6.1.0.exe -o CMakeFiles/cmTC_5e0c4.dir/testCCompiler.c.o -c /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/testCCompiler.c
i686-w64-mingw32-gcc-6.1.0.exe: error: /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/testCCompiler.c: No such file or directory
i686-w64-mingw32-gcc-6.1.0.exe: fatal error: no input files
compilation terminated.
make[1]: *** [CMakeFiles/cmTC_5e0c4.dir/build.make:66: CMakeFiles/cmTC_5e0c4.dir/testCCompiler.c.o] Fehler 1
make[1]: Verzeichnis „/cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp“ wird verlassen
make: *** [Makefile:126: cmTC_5e0c4/fast] Fehler 2
As I see it, the file testCCompiler.c is missing while running gcc-6.1.0.
But when I compile it manually after cmake has failed, it runs successfully. When I run make in the specific directory it works as well (BUT: compiler identification is 6.4.0 while my custom compiler id is 6.1.0).
Running mingw32-make manually for testCCompiler.c:
/usr/bin/cmake.exe -H/cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp -B/cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp --check-build-system CMakeFiles/Makefile.cmake 0
-- The C compiler identification is GNU 6.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp
/usr/bin/cmake.exe -E cmake_progress_start /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/CMakeFiles /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/CMakeFiles/progress.marks
C:/Cygwin/opt/mingw32-1.6.0/bin/mingw32-make -f CMakeFiles/Makefile2 all
mingw32-make[1]: Entering directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
C:/Cygwin/opt/mingw32-1.6.0/bin/mingw32-make -f CMakeFiles/cmTC_033c1.dir/build.make CMakeFiles/cmTC_033c1.dir/depend
mingw32-make[2]: Entering directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
cd /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp && /usr/bin/cmake.exe -E cmake_depends "Unix Makefiles" /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/CMakeFiles/cmTC_033c1.dir/DependInfo.cmake --color=
Scanning dependencies of target cmTC_033c1
mingw32-make[2]: Leaving directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
C:/Cygwin/opt/mingw32-1.6.0/bin/mingw32-make -f CMakeFiles/cmTC_033c1.dir/build.make CMakeFiles/cmTC_033c1.dir/build
mingw32-make[2]: Entering directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
[ 50%] Building C object CMakeFiles/cmTC_033c1.dir/testCCompiler.c.o
/usr/bin/cc -o CMakeFiles/cmTC_033c1.dir/testCCompiler.c.o -c /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/testCCompiler.c
[100%] Linking C executable cmTC_033c1.exe
/usr/bin/cmake.exe -E cmake_link_script CMakeFiles/cmTC_033c1.dir/link.txt --verbose=1
/usr/bin/cc -Wl,--enable-auto-import CMakeFiles/cmTC_033c1.dir/testCCompiler.c.o -o cmTC_033c1.exe -Wl,--out-implib,libcmTC_033c1.dll.a -Wl,--major-image-version,0,--minor-image-version,0
mingw32-make[2]: Leaving directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
[100%] Built target cmTC_033c1
mingw32-make[1]: Leaving directory 'D:/programming/cpp/T2D/build/CMakeFiles/CMakeTmp'
/usr/bin/cmake.exe -E cmake_progress_start /cygdrive/d/programming/cpp/T2D/build/CMakeFiles/CMakeTmp/CMakeFiles 0
My top level CMakeLists.txt is just a simple one, for testing my toolchain configuration:
cmake_minimum_required(VERSION 2.8)
project(T2D)
add_executable(T2D main.cpp)
The cmake command is in a seperate bash file and looks like this:
cmake .. --debug-trycompile -DCMAKE_C_COMPILER=i686-w64-mingw32-gcc-6.1.0 \
-DCMAKE_CXX_COMPILER=i686-w64-mingw32-g++ \
-DCMAKE_LIBRARY_PATH="/opt/mingw32-1.6.0/lib/gcc/i686-w64-mingw32/6.1.0 /opt/mingw32-1.6.0/i686-w64-mingw32/lib" \
-DCMAKE_INCLUDE_PATH="/opt/mingw32-1.6.0/lib/gcc/i686-w64-mingw32/6.1.0/include /opt/mingw32-1.6.0/lib/gcc/i686-w64-mingw32/6.1.0/include-fixed /opt/mingw32-1.6.0/lib/gcc/i686-w64-mingw32/6.1.0/include/c++ /opt/mingw32-1.6.0/i686-w64-mingw32/include/"
Does anyone see what's going wrong, besides the wrong compiler identification? (How does that happen anyway? I've already tried setting the CC and CXX vars too, but that still doesnt change anything; make and mingw32-make still always use 6.4.0 instead of 6.1.0)