Revert "build-compiler-rt: Stop setting CMAKE_*_COMPILER_WORKS"

This reverts commit 056cb22fb5.

The fix for avoiding needing to set CMAKE_*_COMPILER_WORKS,
which means setting CMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
when intiailizing the CMake project setup, was only possible to
apply on compiler-rt/lib/builtins, not other similar projects
like libunwind/libcxxabi/libcxx - so it's expected to keep needing
to set the CMAKE_*_COMPILER_WORKS flags.

Therefore it's also possible that the code in compiler-rt/lib/builtins
could be reverted, as it does have some other minor inconveniences
(it causes some other feature detections to fail, even if they're
harmless within the builtins).

Thus keep setting CMAKE_*_COMPILER_WORKS everywhere consistently.

build-compiler-rt.sh

@@ -110,6 +110,8 @@ for arch in $ARCHS; do
         -DCMAKE_SYSTEM_NAME=Windows \
         -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
         -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
+        -DCMAKE_C_COMPILER_WORKS=1 \
+        -DCMAKE_CXX_COMPILER_WORKS=1 \
         -DCMAKE_C_COMPILER_TARGET=$arch-windows-gnu \
         -DCOMPILER_RT_DEFAULT_TARGET_ONLY=TRUE \
         -DCOMPILER_RT_USE_BUILTINS_LIBRARY=TRUE \