FortranCInterface/Detect: Broken with GCC 12.0 and LTO enabled

Fortran/C interface detection is broken when LTO is enabled with GCC (gfortran) 12.0.

Minimal reproducer:

CMakeLists.txt:

PROJECT(F-C-MWE LANGUAGES C Fortran) 
include(FortranCInterface)
FortranCInterface_HEADER(FCMangle.h
                        MACRO_NAMESPACE "FC_"
                        SYMBOL_NAMESPACE "FC_"
                        SYMBOLS mysub mymod:my_sub)
FortranCInterface_VERIFY()

On shell:

export CFLAGS='-flto'
export FFLAGS='-flto'
export FCFLAGS='-flto'
cmake .

Result (some lines suppressed for legibility):

-- Detecting Fortran/C Interface - Failed to recognize symbols
    CMake Warning (dev) at /usr/share/cmake/Modules/FortranCInterface.cmake:309 (message):
    No FortranCInterface mangling known for mysub

    CMake Warning (dev) at /usr/share/cmake/Modules/FortranCInterface.cmake:295 (message):
    No FortranCInterface mangling known for mymod:my_sub

    -- Verifying Fortran/C Compiler Compatibility
    CMake Warning (dev) at /usr/share/cmake/Modules/FortranCInterface.cmake:309 (message):
    No FortranCInterface mangling known for VerifyFortran

    -- Verifying Fortran/C Compiler Compatibility - Failed
    CMake Error at /usr/share/cmake/Modules/FortranCInterface.cmake:391 (message):

        /usr/bin/ld: /tmp/cclMYidY.ltrans0.ltrans.o: in function `main':
        /usr/share/cmake/Modules/FortranCInterface/Verify/main.c:14: undefined reference to `VerifyFortran'
        collect2: error: ld returned 1 exit status