[CMake] TRY_RUN wrong program return value with --debug-compile

[Eduardo Alberto Hernández Muñoz]

Hi list,

I'm having a new problem with CMake; if anyone cares/remembers the
past one, it was just a stupid typo in the filename.

I have the file check_openal_spec_version_1_1.cpp which contains:

    #define AL_VERSION_1_1
    #define AL_VERSION_1_0

    int main()  {

    #ifdef AL_VERSION_1_1
        return 2;
    #elif AL_VERSION_1_0
        return 1;
    #else
        return -1;
    #endif

    }

and I have this command in the file FindOpenAL.cmake:

    TRY_RUN (
        OPENAL_VERSION
        OPENAL_COMPILED
        ${CMAKE_BINARY_DIR}
        ${BUILD_DIR}check_openal_spec_version_1_1.cpp
        COMPILE_DEFINITIONS "-I${OPENAL_INCLUDE_DIR}"
        )

The problem is that OPENAL_VERSION 80% of the time is 0, but sometimes
is 1, and sometimes 2, never anything else. The correct value returned
should be always 2. OPENAL_COMPILED is always TRUE.

I have another module which uses returns as a mean to get the version
using #defines, and when the OpenAL check goes on ( OPENAL_VERSION is
either 1 or 2 ), the second module has the same issue, returning 0 in
the TRY_RUN().

The interesting part, is that this problem only happens when I pass
the --debug-trycompile to cmake. Without the flag, CMake works
wonderfully.

-Coz