Move the -i[no-]system-prefix options from CC1Options.td to Options.td.

Summary:
This allows them to be used without -cc1 the same way as -I and -isystem.
Renamed the options to --system-header-prefix=/--no-system-header-prefix to avoid interference with -isystem and make the intent of the option cleaner.

Reviewers: rsmith

Reviewed By: rsmith

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3185

llvm-svn: 204775
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index f31c8c0..d744865 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1019,12 +1019,12 @@
   }
 
   // Add the path prefixes which are implicitly treated as being system headers.
-  for (arg_iterator I = Args.filtered_begin(OPT_isystem_prefix,
-                                            OPT_ino_system_prefix),
+  for (arg_iterator I = Args.filtered_begin(OPT_system_header_prefix,
+                                            OPT_no_system_header_prefix),
                     E = Args.filtered_end();
        I != E; ++I)
-    Opts.AddSystemHeaderPrefix((*I)->getValue(),
-                               (*I)->getOption().matches(OPT_isystem_prefix));
+    Opts.AddSystemHeaderPrefix(
+        (*I)->getValue(), (*I)->getOption().matches(OPT_system_header_prefix));
 
   for (arg_iterator I = Args.filtered_begin(OPT_ivfsoverlay),
        E = Args.filtered_end(); I != E; ++I)