Fix duplicate HTTP headers

When the same header is passed in, Apache/PHP will comma delimit
all header values for the returned values in apache_request_headers
and $_SERVER['HTTP_*'].

hphp/runtime/base/server/http_protocol.cpp

@@ -29,6 +29,7 @@
 #include "hphp/runtime/base/server/replay_transport.h"
 #include "hphp/runtime/base/server/virtual_host.h"
 #include "hphp/runtime/base/util/http_client.h"
+#include "folly/String.h"
 
 #define DEFAULT_POST_CONTENT_TYPE "application/x-www-form-urlencoded"
 
@@ -281,10 +282,10 @@ void HttpProtocol::PrepareSystemVariables(Transport *transport,
       }
     }
 
-    for (unsigned int i = 0; i < values.size(); i++) {
+    {
       String key = "HTTP_";
       key += StringUtil::ToUpper(iter->first).replace("-", "_");
-      server.set(key, String(values[i]));
+      server.set(key, String(folly::join(", ", values)));
     }
   }
 

hphp/runtime/ext/ext_apache.cpp

@@ -20,6 +20,7 @@
 #include "hphp/runtime/base/runtime_option.h"
 #include "hphp/runtime/base/server/server_note.h"
 #include "hphp/runtime/base/server/transport.h"
+#include "folly/String.h"
 
 namespace HPHP {
 ///////////////////////////////////////////////////////////////////////////////
@@ -45,7 +46,7 @@ Array f_apache_request_headers() {
     for (HeaderMap::const_iterator iter = headers.begin();
          iter != headers.end(); ++iter) {
       const vector<string> &values = iter->second;
-      ret.set(String(iter->first), String(values.back()));
+      ret.set(String(iter->first), String(folly::join(", ", values)));
     }
     return ret;
   }