re PR pch/68176 (all pch tests fail on eglibc systems (with bits/predefs.h))

	PR pch/68176
	* files.c (_cpp_find_file): Set file->implicit_preinclude even if
	included from file->implicit_preinclude header.

From-SVN: r232956

libcpp/ChangeLog

 2016-01-28  Jakub Jelinek  <jakub@redhat.com>
 
+	PR pch/68176
+	* files.c (_cpp_find_file): Set file->implicit_preinclude even if
+	included from file->implicit_preinclude header.
+
 	* directives.c (destringize_and_run): Adjust prototype.
 
 2016-01-27  David Malcolm  <dmalcolm@redhat.com>

libcpp/files.c

@@ -522,7 +522,10 @@ _cpp_find_file (cpp_reader *pfile, const char *fname, cpp_dir *start_dir,
     return entry->u.file;
 
   file = make_cpp_file (pfile, start_dir, fname);
-  file->implicit_preinclude = implicit_preinclude;
+  file->implicit_preinclude
+    = (implicit_preinclude
+       || (pfile->buffer
+	   && pfile->buffer->file->implicit_preinclude));
 
   /* Try each path in the include chain.  */
   for (; !fake ;)