http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55304
--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> 2012-11-13 11:27:39 UTC --- One problem is AM_PROG_LIBTOOL, which is the part of libtool. GCC autoconf doesn't use libtool since we have in-tree libtool. To use GCC autoconf, we need also use the rest of libtool support in GCC source tree. That means it will make libsanitizer depends on GCC source tree.