Include SSIZE_MAX from limits.h

The existing includes don't pull in limits.h on FreeBSD breaking
the build on FreeBSD.

src/common.c

@@ -7,6 +7,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>