C++ GM clang fix

gistfile1.diff

diff --git a/Makefile b/Makefile
index 186ef46..84c8dfd 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ all: pptoken
 
 # build pptoken application
 pptoken: pptoken.cpp IPPTokenStream.h DebugPPTokenStream.h
-       g++ -g -std=gnu++11 -Wall -o pptoken pptoken.cpp
+       clang++ -g -std=c++11 -stdlib=libc++ -Wall -o pptoken pptoken.cpp
 
 # test pptoken application
 test: all
diff --git a/pptoken.cpp b/pptoken.cpp
index 95e2459..51c4a5e 100644
--- a/pptoken.cpp
+++ b/pptoken.cpp
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <unordered_map>
 #include <unordered_set>
+#include <vector>
 
 using namespace std;