Ignore target feature flags in _AC_FC_LIBRARY_LDFLAGS (#111353)

Ignore target feature flags in _AC_FC_LIBRARY_LDFLAGS (#111353)

Ignore target specific feature flags passed via '-target-feature'.
When encountered, ignore the flag passed after. These flags might
contain a '-l', e.g. '-target-feature -lwp', causing non-existent
libraries to be picked up, failing later checks, or the build of
the application.

This can e.g. be encountered when '-march=native' is passed to
configure during a build with LLVM on Zen 4 machines.

Reported by, and patch written by, Jan André Reuter <j.reuter@fz-juelich.de>.

* lib/autoconf/fortran.m4 (_AC_FC_LIBRARY_LDFLAGS): Skip arguments
  immediately following ‘-target-feature’.