mips-elf-gcc: _libc_name_p missing

[rurban (Reini Urban)]

The mips-elf-gcc post fails on 15.6.0, cc 8.0.0 with _libc_name_p missing. mips-elf-gcc @3.4.6 (cross, devel), no variant

... /usr/bin/clang -c -Os -DLIBICONV_PLUG -DIN_GCC -DCROSS_COMPILE -W -Wall -Wwrite-strin gs -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -DHAVE_CONFIG_H -DGENERATOR_ FILE -I. -I. -I/opt/local/var/macports/build/_opt_local_var_macports_sources_nue.de.rsync.macport s.org_macports_release_tarballs_ports_cross_mips-elf-gcc/mips-elf-gcc/work/gcc-3.4.6/gcc -I/opt/loca l/var/macports/build/_opt_local_var_macports_sources_nue.de.rsync.macports.org_macports_release_tarb alls_ports_cross_mips-elf-gcc/mips-elf-gcc/work/gcc-3.4.6/gcc/. -I/opt/local/var/macports/build/_opt _local_var_macports_sources_nue.de.rsync.macports.org_macports_release_tarballs_ports_cross_mips-elf -gcc/mips-elf-gcc/work/gcc-3.4.6/gcc/../include -I../intl /opt/local/var/macports/build/_opt_local_v ar_macports_sources_nue.de.rsync.macports.org_macports_release_tarballs_ports_cross_mips-elf-gcc/mips-elf-gcc/work/gcc-3.4.6/gcc/fix-header.c -o fix-header.o

:info:build Undefined symbols for architecture x86_64:
:info:build   "_libc_name_p", referenced from:
:info:build       _nothrow_libfn_p in except.o
:info:build ld: symbol(s) not found for architecture x86_64