Teach the driver on Linux to respect -nodefaultlibs.

Patch from Andrew C. Morrow.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156771 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/nodefaultlib.c b/test/Driver/nodefaultlib.c
new file mode 100644
index 0000000..518928a
--- /dev/null
+++ b/test/Driver/nodefaultlib.c
@@ -0,0 +1,8 @@
+// RUN: %clang -target i686-pc-linux-gnu -### -nodefaultlibs %s 2> %t
+// RUN: FileCheck < %t %s
+//
+// CHECK-NOT: start-group
+// CHECK-NOT: -lgcc
+// CHECK-NOT: -lc
+// CHECK: crtbegin
+// CHECK: crtend