* cppinit.c (remove_dup_dir): Add head_ptr argument to handle removal

	at head.
	(remove_dup_nonsys_dirs): New function.
	(remove_dup_dirs): Change argument head to head_ptr.  Remove warnings.
	(merge_include_chains): Remove non-system include directories from
	quote and bracket include chains when they duplicate equivalent system
	directories.
	* doc/cpp.texi (-I): Update.
        * doc/cppopts.texi (-I): Update.
        * doc/install.texi (--with-local-prefix): Further document usage of
	this option.
	* doc/invoke.texi (-I): Update.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@56468 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 5 insertions, 7 deletions

diff --git a/gcc/doc/cppopts.texi b/gcc/doc/cppopts.texi
index b23c9fccdc7..e2265eb9bd6 100644
--- a/gcc/doc/cppopts.texi
+++ b/gcc/doc/cppopts.texi
@@ -51,16 +51,14 @@ for header files.
 @xref{Search Path}.
 @end ifset
 Directories named by @option{-I} are searched before the standard
-system include directories.
-
-It is dangerous to specify a standard system include directory in an
-@option{-I} option.  This defeats the special treatment of system
-headers
+system include directories.  If the directory @var{dir} is a standard
+system include directory, the option is ignored to ensure that the
+default search order for system directories and the special treatment
+of system headers are not defeated
 @ifset cppmanual
 (@pxref{System Headers})
 @end ifset
-.  It can also defeat the repairs to buggy system headers which GCC
-makes when it is installed.
+.
 
 @item -o @var{file}
 @opindex o