Fix mac build with vp9 ratectrl interface

Add -std=c++11 for darwin build.

Change-Id: I760d4f7096bc33520c02b2cd7000fed9ac6cdd90

diff --git a/configure b/configure
index 41c3c6f..32272ce 100755 (executable)
--- a/configure
+++ b/configure
@@ -734,6 +734,7 @@ process_toolchain() {
             # GTestLog must be modified to use Android logging utilities.
         ;;
         *-darwin-*)
+            check_add_cxxflags -std=c++11
             # iOS/ARM builds do not work with gtest. This does not match
             # x86 targets.
         ;;