CMake: Fix detection of linker availability

Previously we passed flags like -ld-fuse=lld only to compile
calls, but not to the link call of a compile test project.

Make sure to pass it to the link call instead by using
check_cxx_source_compiles + CMAKE_REQUIRED_LINK_OPTIONS
instead of
check_cxx_compiler_flag.

Note the flag that is passed is still via passed via the
compiler launcher and not directly to the linker.

Remove duplicate flag handling code.

Pick-to: 6.2 6.3
Change-Id: I1bf90573904a9df83240b6debfee3cc9e425c6bb
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

0 files changed, 0 insertions, 0 deletions