Toolchain: Handle repeated invocations of CMake with -DCMAKE_C_COMPILER

Repeated invocations of `cmake ... -DCMAKE_C_COMPILER=gcc` should not
trigger a "You have changed variables" message even though the cache
value of CMAKE_C_COMPILER changes from '/path/to/gcc' to 'gcc'.

Make repeated invocations of `cmake ... -DCMAKE_C_COMPILER=gcc;-pipe`
not trigger the warning by comparing the compiler name portion of the list to
the compiler being used.
2 files changed