Debug GStreamer execution

Allow to config gstreamer log level

src/shared/shl_log.c

@@ -85,6 +85,8 @@ const char *LOG_SUBSYSTEM = NULL;
 
 unsigned int log_max_sev = LOG_NOTICE;
 
+char *gst_debug = NULL;
+
 /*
  * Forward declaration so we can use the locked-versions in other functions
  * here. Be careful to avoid deadlocks, though.

src/shared/shl_log.h

@@ -61,6 +61,11 @@ enum log_severity {
 
 extern unsigned int log_max_sev;
 
+/*
+ * Defines the debug configuration for gstreamer
+ */
+extern char* gst_debug;
+
 /*
  * Timestamping
  * Call this to initialize timestamps and cause all log-messages to be prefixed