[Bug driver/70936] Hard-coded C++ header paths and relocation problem on Windows

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70936

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This problem does not exiast for a native compiler on GNU/Linux.

Installation in $PREFIX=$HOME/gcc/6.1.0:

ignoring nonexistent directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../x86_64-pc-linux-gnu/include"
ignoring duplicate directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0"
ignoring duplicate directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/x86_64-pc-linux-gnu"
ignoring duplicate directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/backward"
ignoring duplicate directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include"
ignoring duplicate directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include-fixed"
ignoring nonexistent directory
"/home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0

/home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/x86_64-pc-linux-gnu

/home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/backward
 /home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include
 /home/jwakely/gcc/6.1.0/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include-fixed
 /usr/local/include
 /home/jwakely/gcc/6.1.0/bin/../lib/gcc/../../include
 /usr/include
End of search list.
GNU C++14 (GCC) version 6.1.0 (x86_64-pc-linux-gnu)

After relocating to /tmp/gcc:

ignoring nonexistent directory
"/tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../x86_64-pc-linux-gnu/include"
ignoring duplicate directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0"
ignoring duplicate directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/x86_64-pc-linux-gnu"
ignoring duplicate directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/backward"
ignoring duplicate directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include"
ignoring duplicate directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include-fixed"
ignoring nonexistent directory
"/tmp/gcc/bin/../lib/gcc/../../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0

/tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/x86_64-pc-linux-gnu

/tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/../../../../include/c++/6.1.0/backward
 /tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include
 /tmp/gcc/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0/include-fixed
 /usr/local/include
 /tmp/gcc/bin/../lib/gcc/../../include
 /usr/include
End of search list.
GNU C++14 (GCC) version 6.1.0 (x86_64-pc-linux-gnu)

The paths are the same except for the prefix, as expected.