[Bug c/56280] New: GCC builded for MinGW32(-w64) contains malformed directory in include search path

["karlson2k at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56280

             Bug #: 56280
           Summary: GCC builded for MinGW32(-w64) contains malformed
                    directory in include search path
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: karlson2k@gmail.com
              Host: i686-pc-mingw32
            Target: i686-pc-mingw32, i686-w64-mingw32, x86_64-w64-mingw32
             Build: i686-pc-mingw32


Test run:

$ echo int main(){return 1;} | i686-w64-mingw32-gcc.exe -v -E -x c -
Using built-in specs.
COLLECT_GCC=i686-w64-mingw32-gcc.exe
Target: i686-w64-mingw32
Configured with: ../../source/gcc-4.7.2/configure --build=i686-pc-mingw32
--host=i686-pc-mingw32 --target=i686-w64-mingw32 --disable-nls
--disable-multilib --prefix=/home/UserName/mingw-w64/mingw-w64-i686
--with-sysroot=/home/UserName/mingw-w64/mingw-w64-i686
--with-native-system-header-dir=/i686-w64-mingw32/include
--with-host-libstdcxx=/mingw/lib/gcc/mingw32/4.7.2/libstdc++.a
--disable-cloog-version-check --disable-ppl-version-check
--with-mpc=/home/UserName/mingw-w64/packages/gcc/packages/mpc/mpc-1.0.1-i686
--with-mpfr=/home/UserName/mingw-w64/packages/gcc/packages/mpfr/mpfr-3.1.1-i686
--with-gmp=/home/UserName/mingw-w64/packages/gcc/packages/gmp/gmp-5.1.0-i686
--with-ppl=/home/UserName/mingw-w64/packages/gcc/packages/ppl/ppl-1.0-i686
--with-cloog=/home/UserName/mingw-w64/packages/gcc/packages/cloog-ppl/cloog-ppl-0.15.11-i686
--enable-languages=c,c++ --enable-threads=win32 --enable-fully-dynamic-string
--disable-sjlj-exceptions --with-multilib-list=m32 --with-arch=pentium3
--enable-leading-mingw64-underscores --with-dwarf2 --enable-lto
--disable-win32-registry --with-win32-nlsapi=unicode --enable-libstdcxx-debug
Thread model: win32
gcc version 4.7.2 (GCC)
COLLECT_GCC_OPTIONS='-v' '-E' '-mtune=generic' '-march=pentium3'

t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../libexec/gcc/i686-w64-mingw32/4.7.2/cc1.exe
-E -quiet -v -iprefix
t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../lib/gcc/i686-w64-mingw32/4.7.2/
-isysroot
t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../../mingw-w64-i686
-U_REENTRANT - -mtune=generic -march=pentium3
ignoring duplicate directory
"T:/MinGW32/msys/1.0/home/UserName/mingw-w64/mingw-w64-i686/lib/gcc/../../lib/gcc/i686-w64-mingw32/4.7.2/include"
ignoring nonexistent directory
"t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../../mingw-w64-i686T:/MinGW32/msys/1.0/home/UserName/mingw-w64/mingw-w64-i686/lib/gcc/i686-w64-mingw32/4.7.2/../../../../include"
ignoring duplicate directory
"T:/MinGW32/msys/1.0/home/UserName/mingw-w64/mingw-w64-i686/lib/gcc/../../lib/gcc/i686-w64-mingw32/4.7.2/include-fixed"
ignoring duplicate directory
"T:/MinGW32/msys/1.0/home/UserName/mingw-w64/mingw-w64-i686/lib/gcc/../../lib/gcc/i686-w64-mingw32/4.7.2/../../../../i686-w64-mingw32/include"
ignoring nonexistent directory
"t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../../mingw-w64-i686/mingw/include"
#include "..." search starts here:
#include <...> search starts here:

t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../lib/gcc/i686-w64-mingw32/4.7.2/include

t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../lib/gcc/i686-w64-mingw32/4.7.2/include-fixed

t:\mingw32\msys\1.0\home\username\mingw-w64\mingw-w64-i686\bin\../lib/gcc/i686-w64-mingw32/4.7.2/../../../../i686-w64-mingw32/include
End of search list.
# 1 "<stdin>"
# 1 "<command-line>"
# 1 "<stdin>"
int main(){return 1;}
COMPILER_PATH=t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../libexec/gcc/i686-w64-mingw32/4.7.2/;t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../libexec/gcc/;t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../lib/gcc/i686-w64-mingw32/4.7.2/../../../../i686-w64-mingw32/bin/
LIBRARY_PATH=t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../lib/gcc/i686-w64-mingw32/4.7.2/;t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../lib/gcc/;t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../lib/gcc/i686-w64-mingw32/4.7.2/../../../../i686-w64-mingw32/lib/../lib/;t:/mingw32/msys/1.0/home/username/mingw-w64/mingw-w64-i686/bin/../lib/gcc/i686-w64-mingw32/4.7.2/../../../../i686-w64-mingw32/lib/
COLLECT_GCC_OPTIONS='-v' '-E' '-mtune=generic' '-march=pentium3'

See "ignoring nonexistent directory" - two paths are glued together.
This could be related to bug 56279 and bug 52947.