audio/mumble-server: fix build on i386

/wrkdirs/usr/ports/audio/mumble-server/work/mumble-1.5.613/src/murmur/Server.cpp:1044:21:
error: implicit conversion changes signedness: 'int' to 'std::vector<char>::size_type'
(aka 'unsigned int') [-Werror,-Wsign-conversion]
                bufVec.resize(len + 4);
                       ~~~~~~ ~~~~^~~
1 error generated.

Upstream issue: mumble-voip/mumble#6377

Reported by:	pkg-fallout
Approved by:	arrowd (mentor, implicit)
MFH:		2024Q2

audio/mumble-server/files/patch-src_murmur_Server.cpp

@@ -0,0 +1,11 @@
+--- src/murmur/Server.cpp.orig	2024-03-03 17:26:27 UTC
++++ src/murmur/Server.cpp
+@@ -1041,7 +1041,7 @@ void Server::sendMessage(ServerUser &u, const unsigned
+ 			((reinterpret_cast< quint64 >(ebuffer.data()) + 8) & static_cast< quint64 >(~7)) + 4);
+ #else
+ 		std::vector< char > bufVec;
+-		bufVec.resize(len + 4);
++		bufVec.resize(static_cast< std::size_t >(len + 4));
+ 		char *buffer    = bufVec.data();
+ #endif
+ 		{