Fix cmake ipv6 detection

src/CMakeLists.txt

@@ -1,3 +1,4 @@
+INCLUDE(CheckCSourceCompiles)
 INCLUDE(CheckIncludeFiles)
 INCLUDE(CheckFunctionExists)
 INCLUDE(CheckVariableExists)
@@ -104,7 +105,15 @@ CHECK_FUNCTION_EXISTS(strptime HAVE_STRPTIME)
 CHECK_FUNCTION_EXISTS(syslog HAVE_SYSLOG)
 CHECK_FUNCTION_EXISTS(writev HAVE_WRITEV)
 CHECK_FUNCTION_EXISTS(inet_aton HAVE_INET_ATON)
-CHECK_FUNCTION_EXISTS(inet_atop HAVE_IPV6)
+CHECK_C_SOURCE_COMPILES("
+	#include <sys/types.h>
+	#include <sys/socket.h>
+	#include <netinet/in.h>
+	
+	int main() {
+		struct sockaddr_in6 s; struct in6_addr t=in6addr_any; int i=AF_INET6; s; t.s6_addr[0] = 0;
+		return 0;
+	}" HAVE_IPV6)
 
 ## refactor me
 MACRO(XCONFIG _package _include_DIR _link_DIR _link_FLAGS _cflags)

src/config.h.cmake

@@ -23,6 +23,7 @@
 #cmakedefine HAVE_UNISTD_H
 #cmakedefine HAVE_PTHREAD_H
 #cmakedefine HAVE_INET_ATON
+#cmakedefine HAVE_IPV6
 
 /* XATTR */
 #cmakedefine HAVE_ATTR_ATTRIBUTES_H