fix segfault in DNS mapping lookup code

the allocatorthread got pointers to RAM which were reallocated
behind the back, and if realloc() couldn't grow in-place, lead
to segfaults in applications that do a lot of DNS-lookups such
as webbrowsers.

closes #66
closes #31

thanks to @ravomavain for tracking down the issue.

src/allocator_thread.c

@@ -10,12 +10,10 @@
 #include <stddef.h>
 #include <errno.h>
 #include "allocator_thread.h"
-#include "shm.h"
 #include "debug.h"
 #include "ip_type.h"
 #include "mutex.h"
 #include "hash.h"
-#include "stringdump.h"
 
 /* stuff for our internal translation table */
 
@@ -30,6 +28,12 @@ typedef struct {
 	string_hash_tuple** list;
 } internal_ip_lookup_table;
 
+static void *dumpstring(char* s, size_t len) {
+	char* p = malloc(len);
+	if(p) memcpy(p, s, len);
+	return p;
+}
+
 pthread_mutex_t internal_ips_lock;
 internal_ip_lookup_table *internal_ips = NULL;
 internal_ip_lookup_table internal_ips_buf;