Fix some mishandling of the attr(gnu_inline) mode when used with
extern.  Previously we would warn about it and ignore the attribute.
This is incorrect, it should be handled as a c89 "extern inline" 
function.  Many thanks to Matthieu Castet for pointing this out and
beating me over the head until I got it.

PR3988: extern inline function are not externally visible




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69756 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/function.c b/test/Sema/function.c
index fa99830..77557c9 100644
--- a/test/Sema/function.c
+++ b/test/Sema/function.c
@@ -64,7 +64,7 @@
 
 
 extern __inline
-__attribute__((__gnu_inline__))  // expected-warning{{'gnu_inline' attribute is overridden by 'extern inline', attribute ignored}} expected-warning{{extension used}}
+__attribute__((__gnu_inline__))  // expected-warning{{extension used}}
 void gnu_inline1() {}
 
 void