fix for -fno-common

Index: src/main.c
--- src/main.c.orig
+++ src/main.c
@@ -47,6 +47,7 @@
 #include <dmalloc.h>
 #endif /* HAVE_LIBDMALLOC */
 
+option_t config;
 regex_t posix_pattern;
 #ifdef HAVE_LIBPCRE
 pcre *pcre_pattern;
