Hi. As of 991180627851801f1999d1ebbc0e569a17e47c74 GMP and MPFR configuration is now moved to toplevel configure. However, if gdb is disabled with --disable-gdb the toplevel configure still applies require_gmp=yes if the source directory ${srcdir}/gdb exists. However, this check should honor --disable-gdb (i.e. noconfigdirs) and not only test for the source directory existence.
I met the same issue and work it around by removing the gdb directory.
Was fixed by this commit: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=5fb0e308577143ceb313fde5538dc9ecb038f29f