libgfortran: Set GFORTRAN

The libgfortran configure sets FC to be $GFORTRAN. We did used to patch
that out but rather than carry a patch to gcc, just set GFORTRAN as
needed.

(From OE-Core rev: 4ec096a9ce8a49b631efc50e7d95ff653d4c4374)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gcc/libgfortran.inc

@@ -5,6 +5,11 @@ EXTRA_OECONF_PATHS = "\
     --with-build-sysroot=${STAGING_DIR_TARGET} \
 "
 
+# An arm hard float target like raspberrypi4 won't build
+# as CFLAGS don't make it to the fortran compiler otherwise
+# (the configure script sets FC to $GFORTRAN unconditionally)
+export GFORTRAN = "${FC}"
+
 do_configure () {
 	for target in libbacktrace libgfortran
 	do