include paths missing

[Torsten Mueller]

I have an interesting question. I specify -I. and -I../.. during the g++
invocation. But the compiler doesn't know these paths. Why?

Look at this example:

$ g++ -v -I. -I../.. -c config.cc

The -v makes gcc dump the following list before compilation:

[...]
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/i686-pc-linux-gnu/4.7.1/../../../../include/c++/4.7.1
/usr/lib/gcc/i686-pc-linux-gnu/4.7.1/../../../../include/c++/4.7.1/i686-pc-linux-gnu
/usr/lib/gcc/i686-pc-linux-gnu/4.7.1/../../../../include/c++/4.7.1/backward
/usr/lib/gcc/i686-pc-linux-gnu/4.7.1/include
/usr/local/include
/usr/lib/gcc/i686-pc-linux-gnu/4.7.1/include-fixed
/usr/include
End of search list.
End of search list.
[...]

What's wrong here? I have another machine where . and ../.. are
mentioned at the top of the list and everything is fine. But here gcc
doesn't find the headers. What could be a reason for this? I really have
no idea.

gcc 4.7.1 on Arch Linux

T.M.