http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53384
--- Comment #5 from John T <jrt at worldlinc dot net> 2012-05-21 19:55:36 UTC --- This problem I found with 4.6.3 somewhat disappeared after I first used v. 4.4.1 to make gcc-4.6.1 and install. Version 4.6.3 built ok starting with 4.6.1, so I would assume that the problem was with something buggy in 4.4.1 that worked in 4.6.1. But part of the bug is still there. I built just gcc in 4.6.3 to test, then entered "make distclean" and reran configure for a full build. On doing this, I got the error message that the contents of fixinclude/config.cache weren't right, gcc was gcc/xgcc with some flags and it's now just plain gcc. In other words, "make distclean" didn't remove enough previous data to make a clean new reconfigured build. I have installed gcc-4.6.3 and haven't tried another "make distclean" as even if it works correctly to allow a new configuration, the action would throw away hours of runtime and test results and I don't want to do that. I might build gcc alone again in a throw-away folder to see if the problem still arises on trying to reconfigure. "Make distclean" should leave just what was there before unpacking a source tarball, and in the case of gcc's build folder, there was nothing. "Make distclean" might as well result in everything in the build folder being deleted. Experimental computing, trying this and that to discover things that don't work, certainly is time-consuming!