Fix help for --suppress-system-warnings


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@56878 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/clang.cpp b/Driver/clang.cpp
index 9411dd3..8cfdd94 100644
--- a/Driver/clang.cpp
+++ b/Driver/clang.cpp
@@ -524,7 +524,7 @@
 
 static llvm::cl::opt<bool>
 SuppressSystemWarnings("suppress-system-warnings",
-                     llvm::cl::desc("Issue an error on uses of GCC extensions"),
+                       llvm::cl::desc("Suppress warnings issued in system headers"),
                        llvm::cl::init(true));
 
 static llvm::cl::opt<bool>