Add config.h in files were it was missing

Related to https://github.com/profanity-im/profanity/issues/1512

src/log.c

@@ -34,6 +34,8 @@
  *
  */
 
+#include "config.h"
+
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>