use upstream binutils and remove dual linker mess

Remove dual linker mess in favor of using gold always.
Revert "use upstream binutils and remove dual linker mess"

This reverts commit d14c3a7f6dc919d370466a14f1baea428c3831a8.
move --disable-libsanitizer to Makefile.in
move --enable-plugins to Makefile.in
Makefile: add --enable-threads to binutils args
upgrade isl to 0.12.1