core: only generate backtraces if EXTRA_DEBUG is defined.

This fixes build on systems that have no backtrace API in the
libc (e.g. BSDs).

Author: sobomax

io_wait.h

@@ -94,7 +94,9 @@
 #ifdef __OS_linux
 #include <features.h>     /* for GLIBC version testing */
 #endif
+#ifdef EXTRA_DEBUG
 #include "lib/dbg/backtrace.h"
+#endif
 
 #ifndef FD_TYPE_DEFINED
 typedef int fd_type;
@@ -732,13 +734,17 @@ inline static int io_watch_del(io_wait_h* h, int fd, int idx,
 		if (!(idx>=0 && idx<h->fd_no)) {
 			LM_CRIT("[%s] FD index check failed, idx=%d, max=%d"
 				" operating on %d\n",h->name, idx, h->fd_no, fd );
+#ifdef EXTRA_DEBUG
 			log_backtrace();
+#endif
 			rla_dump();
 			idx = -1;
 		} else if (h->fd_array[idx].fd!=fd) {
 			LM_CRIT("[%s] FD consistency check failed, idx=%d points to fd=%d,"
 				" but operating on %d\n",h->name, idx, h->fd_array[idx].fd, fd );
+#ifdef EXTRA_DEBUG
 			log_backtrace();
+#endif
 			rla_dump();
 			idx = -1;
 		}