Revert:
2016-12-02 Tadek Kijkowski <tkijkowski@gmail.com>
* Makefile.in (PREPROCESSOR_DEFINES): Add a level of indirection
for several include directories that may be relative to sysroot.
* config/i386/x-mingw32 (gplus_includedir): Define.
(gplus_tool_includedir, gplus_backward_include_dir): Likewise.
(native_system_includedir): Likewise.
* config/i386/mingw32.h (STANDARD_STARTFILE_PREFIX_1): Do not
override if TARGET_SYSTEM_ROOT is defined.
(NATIVE_SYSTEM_HEADER_DIR): Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@244510 138bc75d-0d04-0410-961f-82ee72b054a4