Driver: Add support for a new -nostdlibinc option.
 - This disables the system include directories, but not the compiler builtin
   directories. Useful for projects that want to use things like the intrinsic
   headers, but are otherwise freestanding.

 - I'm willing to reconsider the option naming, I also considered providing an
   explicit -builtinc (which would match -nobuiltininc), but this is more
   consistent with existing options.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141692 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/tools/clang.pod b/docs/tools/clang.pod
index 704cc87..964b143 100644
--- a/docs/tools/clang.pod
+++ b/docs/tools/clang.pod
@@ -459,7 +459,13 @@
 
 =item B<-nostdinc>
 
-Do not search the standard system directories for include files.
+Do not search the standard system directories or compiler builtin directories
+for include files.
+
+=item B<-nostdlibinc>
+
+Do not search the standard system directories for include files, but do search
+compiler builting include directories.
 
 =item B<-nobuiltininc>