"Joseph S. Myers" <jos...@codesourcery.com> writes:
> On Fri, 7 Oct 2011, Ian Lance Taylor wrote:
>
>> 2011-10-07 Simon Baldwin <sim...@google.com>
>>
>> * configure.ac: Add --with-native-system-header-dir option.
>> * configure: Rebuild from configure.ac.
>> * Makefile.in: Support --with-native-system-header-dir.
>> * doc/install.texi: Document --with-native-system-header-dir.
>
> How does this end up affecting the paths in cppdefault.c, and which of the
> macros there does it affect? (I don't see how STANDARD_INCLUDE_DIR, the
> normal /usr/include path, gets affected by this patch; I can only see how
> it affects the paths used to find inputs to fixincludes.)
Hmmm, you're quite right. Simon's patch works because of a subsequent
patch of his, which adds a --with-runtime-root-prefix configure option.
It looks like we currently have NATIVE_SYSTEM_HEADER_DIR in Makefile
fragments and STANDARD_INCLUDE_DIR and SYSTEM_INCLUDE_DIR in tm.h files.
The documentation for NATIVE_SYSTEM_HEADER_DIR says that it should match
SYSTEM_INCLUDE_DIR. However, in fact, nothing in the tree defines
SYSTEM_INCLUDE_DIR.
NATIVE_SYSTEM_HEADER_DIR is defined by five Makefile fragments:
config/i386/t-djgpp
config/i386/t-mingw-w64
config/i386/t-mingw-w32
config/i386/t-mingw32
config/t-gnu
config/spu/t-spu-elf
STANDARD_INCLUDE_DIR is defined by:
config/i386/djgpp.h
config/i386/mingw32.h
config/spu/spu-elf.h
config/gnu.h
config/vms/xm-vms.h
The uses in DJGPP and Mingw support all match. config/gnu.h is only
used on i[34567]86-*-gnu* while config/t-gnu is used on *-*-gnu*; this
mismatch appears to be an error. The use of STANDARD_INCLUDE_DIR in
config/vms/xm-vms.h without defining NATIVE_SYSTEM_HEADER_DIR appears to
be an error.
The configure script uses "/usr/include" when setting
target_header_dir. This is incorrect when NATIVE_SYSTEM_HEADER_DIR is
defined by a Makefile fragment.
So, it seems to me that we should:
* Remove SYSTEM_INCLUDE_DIR, which is undefined and unnecessary.
* Move the definition of NATIVE_SYSTEM_HEADER_DIR into config.gcc
(named native_system_header_dir). The default is /usr/include.
This appears to be necessary since the configure script itself needs
to know this value.
* Have the configure script use NATIVE_SYSTEM_HEADER_DIR when setting
target_header_dir.
* Arrange for Makefile to define NATIVE_SYSTEM_HEADER_DIR when
compiling cppdefault.c (i.e., add it to PREPROCESSOR_DEFINES in
Makefile.in).
* Replace STANDARD_INCLUDE_DIR in cppdefault.c with
NATIVE_SYSTEM_HEADER_DIR.
* Remove STANDARD_INCLUDE_DIR.
* Add the --with-native-system-header-dir option.
This will remove the setting in vms/xm-vms.h; people using VMS as a host
should be advised to use --with-sysroot instead.
I think this will get us to a consistent state where the name of the
header file directory is defined in one place and is used everywhere it
is appropriate.
Ian
