How to partially disabling cmake C/C++ custom compiler checking - c++

Question

I am trying to do some crosscompilation using cmake. Some are easy with all the examples on Internet, I managed to crosscompile my library on Linux (x86 and ARM), Windows and Android. But now I would like to do it on a custom platform.
The process I need to achieve:
Sourcing my environment (this destroy all previous bash classic environment)
Compile with cmake
Execute what I want
But Cmake is testing for symbols in my custom C/C++ libraries which make my library unable to compile. The errors I have are that cmake some versions of GLIBCXX and CXXABI (no C issues) but not all of them.
Is there a way to make cmake ok with it ?
EDIT:
I tried using:
set(CMAKE_C_COMPILER_WORKS TRUE)
set(CMAKE_CXX_COMPILER_WORKS TRUE)
And with:
include(CMakeForceCompiler)
...
cmake_force_c_compiler(${ENV_PATH}/bin/${CC})
cmake_force_cxx_compiler(${ENV_PATH}/bin/${CXX})
But cmake is still checking for symbols.

Answer 1

Without having your environment nor the error message it's not easy to tell the actual root cause but here are two of the common causes and respective fixes:
If you don't have a complete toolchain file created for your custom environment - so CMake can't link a simple test program - you can try the relatively new (version 3.6) global CMake variable named CMAKE_TRY_COMPILE_TARGET_TYPE.
So just add the following:
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
Then CMake would just try to build a static library.
To have only the most common GCC compiler variables set and have only some basic checks, try:
SET(CMAKE_SYSTEM_NAME Generic)
See CMake Cross Compiling: Setting up the system and toolchain:
If your target is an embedded system without OS set CMAKE_SYSTEM_NAME to "Generic"
References
CMake AMRCC + custom linker
cmake cross-compile with specific linker doesn't pass arguments to armlink

Answer 2

Commandline:
cmake ... \
-DCMAKE_C_COMPILER_FORCED=TRUE \
-DCMAKE_CXX_COMPILER_FORCED=TRUE
or
CMakeLists.txt
...
set(CMAKE_C_COMPILER_FORCED TRUE)
set(CMAKE_CXX_COMPILER_FORCED TRUE)
...
Works for me.