Avoid a type mismatch that shows up in C++11.
Taken from <https://bugs.debian.org/853560>.

--- a/src/rtphint.cpp	2012-05-20 16:11:53.000000000 -0600
+++ b/src/rtphint.cpp	2017-05-16 10:25:26.930705191 -0600
@@ -339,7 +339,7 @@
                 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);
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<tr><td><span title='2021-04-12 18:42:22 +0200'>2021-04-12</span></td><td><a href='/guix/commit/gnu/tests.scm?id=3332f4365bf329c361d650c70e53b8a74ad923bd'>tests: Support package extensions in the backdoor REPL.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests.scm
  (&lt;marionette-configuration&gt;): Add 'extensions' field.
  (marionette-shepherd-service): Honour the field.
  (with-import-modules-and-extensions): Define a combination
  of 'with-import-modules' and 'with-extensions'.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2021-02-19 20:10:08 +0100'>2021-02-19</span></td><td><a href='/guix/commit/gnu/tests.scm?id=f57b7cea748c1e8284373811c13398d9f69aec89'>tests: Export %simple-os.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests.scm (%simple-os): Export it.
</span></span></td><td>Mathieu Othacehe</td></tr>