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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'2020-07-19 14:46:25 +0200'>2020-07-19</span></td><td><a href='/guix/commit/gnu/packages/gd.scm?id=cd6aa38e7fc3e7d9fa1b79db041e8bf7cda39322'>gnu: perl-gd: Update to 2.72 [fixes CVE-2019-6977].</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2020-04-08 14:21:41 +0200'>2020-04-08</span></td><td><a href='/guix/commit/gnu/packages/gd.scm?id=76125bc061b199936c60c348290a593ac3450945'>gnu: perl-gd: Do not rely on 'libgd-config'.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-26 22:35:35 +0100'>2020-03-26</span></td><td><a href='/guix/commit/gnu/packages/gd.scm?id=736d772b82bfd693cd9412e2857e029fa6309269'>gnu: gd: Update to 2.3.0.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
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<tr><td><span title='2020-03-11 03:01:45 +0100'>2020-03-11</span></td><td><a href='/guix/commit/gnu/packages/gd.scm?id=44184f33562f483c32c9ec78db5cef26b3386cfd'>gnu: gd: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>