fix compilation with openbsd

closes #52

configure

@@ -14,6 +14,10 @@ isbsd() {
 	uname -s | grep BSD >/dev/null
 }
 
+isopenbsd() {
+	uname -s | grep OpenBSD >/dev/null
+}
+
 usage() {
 	echo "supported arguments"
 	echo "--prefix=/path 		default: $prefix"
@@ -104,6 +108,7 @@ if ismac ; then
 elif isbsd ; then
 	echo LIBDL=>>config.mak
 	echo "CFLAGS+=-DIS_BSD">>config.mak
+	isopenbsd && echo "CFLAGS+=-DIS_OPENBSD">>config.mak
 	make_cmd=gmake
 fi
 

src/core.c

@@ -785,8 +785,12 @@ void proxy_freeaddrinfo(struct addrinfo *res) {
 	free(res);
 }
 
-#ifdef IS_MAC
-/* getservbyname on mac is using thread local storage, so we dont need mutex */
+#if defined(IS_MAC) || defined(IS_OPENBSD)
+#ifdef IS_OPENBSD /* OpenBSD has its own incompatible getservbyname_r */
+#define getservbyname_r mygetservbyname_r
+#endif
+/* getservbyname on mac is using thread local storage, so we dont need mutex 
+   TODO: check if the same applies to OpenBSD */
 static int getservbyname_r(const char* name, const char* proto, struct servent* result_buf, 
 			   char* buf, size_t buflen, struct servent** result) {
 	PFUNC();
@@ -853,6 +857,9 @@ int proxy_getaddrinfo(const char *node, const char *service, const struct addrin
 		p->ai_flags = hints->ai_flags;
 		p->ai_protocol = hints->ai_protocol;
 	} else {
+#ifndef AI_V4MAPPED
+#define AI_V4MAPPED 0
+#endif
 		p->ai_flags = (AI_V4MAPPED | AI_ADDRCONFIG);
 	}