mp4v2: add upstream patch fixing build issue with gcc 7+

new file mode 100644
index 0000000000..90222c10ae
@@ -0,0 +1,32 @@
+From 855e9674232808ff3be7191b697dfb56917db21f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?S=C3=A9rgio=20M=2E=20Basto?= <[email protected]>
+Date: Wed, 8 Feb 2017 00:56:32 +0000
+Subject: [PATCH] Fix GCC7 build
+
+if (*pSlash != '\0') {
+
+As it stands the body of that if will always execute and when there are
+no encoding parameters ppEncodingParams will be returned as a pointer to
+an empty string rather than as a null pointer
+
+Signed-off-by: Peter Korsgaard <[email protected]>
+---
+ src/rtphint.cpp | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/rtphint.cpp b/src/rtphint.cpp
+index e07309d..1eb01f5 100644
+--- a/src/rtphint.cpp
++++ b/src/rtphint.cpp
+@@ -339,7 +339,7 @@ void MP4RtpHintTrack::GetPayload(
+                 pSlash = strchr(pSlash, '/');
+                 if (pSlash != NULL) {
+                     pSlash++;
+-                    if (pSlash != '\0') {
++                    if (*pSlash != '\0') {
+                         length = (uint32_t)strlen(pRtpMap) - (pSlash - pRtpMap);
+                         *ppEncodingParams = (char *)MP4Calloc(length + 1);
+                         strncpy(*ppEncodingParams, pSlash, length);
+-- 
+2.11.0
+