* gcc.c (option_map): Add --sysroot.

	(process_command): Handle --sysroot.
	(display_help): Document it.
	* doc/cppopts.tex (-isysroot): Document.
	* doc/invoke.texi (--sysroot): Document.
	* doc/install.texi (--with-build-sysroot): Document.

	* Makefile.in (inhibit_libc): New variable.
	(INHIBIT_LIBC_CFLAGS): Likewise.
	(LIBGCC2_CFLAGS): Include
	$(INHIBIT_LIBC_CFLAGS).
	(CRTSTUFF_CFLAGS): Include $(INHIBIT_LIBC_CFLAGS).
	($(T)crtbegin.o): Do not use @inhibit_libc@.
	($(T)crtend.o): Likewise.
	($(T)crtbeginS.o): Do not use @inhibit_libc@.
	($(T)crtendS.o): Likewise.
	($(T)crtbeginT.o): Do not use @inhibit_libc@.
	($(T)crtendT.o): Likewise.
	(stmp-fixinc): Do not complain about missing headers if
	inhibit_libc.
	* configure.ac (inhibit_libc): Set it to true/false.
	(--with-build-sysroot): New option.  Use it to set
	SYSTEM_HEADER_DIR.
	* configure: Regenerated.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@102367 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 34 insertions, 1 deletions

diff --git a/gcc/doc/cppopts.texi b/gcc/doc/cppopts.texi
index 80bbe50e690..2790e8c7734 100644
--- a/gcc/doc/cppopts.texi
+++ b/gcc/doc/cppopts.texi
@@ -478,6 +478,11 @@ Append @var{dir} to the prefix specified previously with
 path.  @option{-iwithprefixbefore} puts it in the same place @option{-I}
 would; @option{-iwithprefix} puts it where @option{-idirafter} would.
 
+@item -isysroot @var{dir}
+@opindex isysroot
+This option is like the @option{--sysroot} option, but applies only to
+header files.  See the @option{--sysroot} option for more information.
+
 @item -isystem @var{dir}
 @opindex isystem
 Search @var{dir} for header files, after all directories specified by
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index ac046c7a7fa..2baf003b95c 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1228,6 +1228,16 @@ in case @option{--with-sysroot} is not given an argument, is
 subdirectory of @option{$@{exec_prefix@}}, then it will be found relative to
 the GCC binaries if the installation tree is moved.
 
+@item --with-build-sysroot
+@itemx --with-build-sysroot=@var{dir}
+Tells GCC to consider @var{dir} as the system root (see
+@option{--with-sysroot}) while building the compiler itself, instead of
+the directory specified with @option{--with-sysroot}.  This option is
+only useful when you are already using @option{--with-sysroot}.  You
+can use @option{--with-build-sysroot} when you are configure with
+@option{--prefix} set to a directory that is different from the one in
+which you are installing GCC and your target libraries.
+
 @item --with-headers
 @itemx --with-headers=@var{dir}
 Deprecated in favor of @option{--with-sysroot}.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 988f13b1dbd..f24505562a7 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -349,6 +349,7 @@ Objective-C and Objective-C++ Dialects}.
 -include @var{file}  -imacros @var{file} @gol
 -iprefix @var{file}  -iwithprefix @var{dir} @gol
 -iwithprefixbefore @var{dir}  -isystem @var{dir} @gol
+-isysroot @var{dir} @gol
 -M  -MM  -MF  -MG  -MP  -MQ  -MT  -nostdinc  @gol
 -P  -fworking-directory  -remap @gol
 -trigraphs  -undef  -U@var{macro}  -Wp,@var{option} @gol
@@ -368,7 +369,8 @@ Objective-C and Objective-C++ Dialects}.
 
 @item Directory Options
 @xref{Directory Options,,Options for Directory Search}.
-@gccoptlist{-B@var{prefix}  -I@var{dir}  -iquote@var{dir}  -L@var{dir}  -specs=@var{file}  -I-}
+@gccoptlist{-B@var{prefix}  -I@var{dir}  -iquote@var{dir}  -L@var{dir}
+-specs=@var{file}  -I- --sysroot=@var{dir}}
 
 @item Target Options
 @c I wrote this xref this way to avoid overfull hbox. -- rms
@@ -6372,6 +6374,22 @@ program uses when determining what switches to pass to @file{cc1},
 @option{-specs=@var{file}} can be specified on the command line, and they
 are processed in order, from left to right.
 
+@item --sysroot=@var{dir}
+@opindex sysroot
+Use @var{dir} as the logical root directory for headers and libraries.
+For example, if the compiler would normally search for headers in
+@file{/usr/include} and libraries in @file{/usr/lib}, it will instead
+search @file{@var{dir}/usr/include} and @file{@var{dir}/usr/lib}.  
+
+If you use both this option and the @option{-isysroot} option, then
+the @option{--sysroot} option will apply to libraries, but the
+@option{-isysroot} option will apply to header files.
+
+The GNU linker (beginning with version 2.16) has the necessary support
+for this option.  If your linker does not support this option, the
+header file aspect of @option{--sysroot} will still work, but the
+library aspect will not.
+
 @item -I-
 @opindex I-
 This option has been deprecated.  Please use @option{-iquote} instead for