enable_language: Assume compiler works if ABI detection compiles
We run a try_compile
with a tiny test source to check if the compiler
works so that we can fail early if it does not. When the compiler does
work, we immediately try_compile
the ABI detection source. In the
common case that both steps work, we gain no useful information from the
first one and the work was wasted.
Re-order the checks to try the ABI detection first. If it works then assume the compiler works and skip the dedicated check. If the ABI check fails then proceed with the normal test for a working compiler so the diagnostic can be shown as before.
Fixes: #18703 (closed)