http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48910
--- Comment #2 from Adam_5Wu at Hotmail dot com 2011-05-06 20:00:06 UTC --- (In reply to comment #1) > But that code is processing an environment variable, and it's absolutely > standard that empty elements in PATH-like environment variables are > processed as ".". > > What environment variable is set to contain an empty element, and how did > it get set like that? The problem is that the environment variable is > set, and the fix must be to stop it from being set. If the variable was > not set by something in GCC, then this is not a GCC bug but a problem with > your build environment. Ahh, thanks for the explanation. Yes, somehow the C_INCLUDE_PATH on my machine contains an empty component. This is a quite obscure problem. I have researched it for quite some time on Google and found many people have similar problem but none had a proper solution or explanation, which leads me to speculate it may be a bug in gcc... For example: http://gcc.gnu.org/ml/gcc-help/2009-11/msg00202.html http://d.hatena.ne.jp/sugyan/20080626 http://ubuntuforums.org/showthread.php?p=7596021 http://forums.gentoo.org/viewtopic-t-797447.html http://betterlogic.com/roger/2008/10/gcc-woe/ This one is close: http://www.spinics.net/lists/gcchelp/msg26054.html The author says unset "C_INCLUDE_PATH" may help but "don't know why", I was afraid of breaking other things so I didn't proceed with that suggestion. So it seems that having an empty component in the gcc path environment variable probably is accidental and doesn't have desired effect most of the time. Probably gcc should print a warning message about it (at least in verbose mode)? In addition, since the building of gcc relies on "." not included in any of the paths, maybe the build script should detect it and fail early?
