Fix build for systems that don't provide POSIX.1-2001 by default

[empserver] / m4 / my_working_in6_is_addr_v4mapped.m4

diff --git a/m4/my_working_in6_is_addr_v4mapped.m4 b/m4/my_working_in6_is_addr_v4mapped.m4
new file mode 100644 (file)
index 0000000..2c47682
--- /dev/null
+++ b/m4/my_working_in6_is_addr_v4mapped.m4
@@ -0,0 +1,20 @@
+AC_DEFUN([MY_WORKING_IN6_IS_ADDR_V4MAPPED], [
+    AC_CACHE_CHECK([whether IN6_IS_ADDR_V4MAPPED works],
+                  my_cv_func_in6_is_addr_v4mapped, [
+       AC_COMPILE_IFELSE(
+           [AC_LANG_SOURCE([[#include <netinet/in.h>
+int foo(struct sockaddr_in6 *sap6)
+{
+    return IN6_IS_ADDR_V4MAPPED(&sap6->sin6_addr);
+}]])],
+           [my_cv_func_in6_is_addr_v4mapped=yes],
+           [my_cv_func_in6_is_addr_v4mapped=no])])
+    AC_CHECK_MEMBERS([struct sockaddr_in6.sin6_addr.s6_addr],
+                    [my_member_sockaddr_in6_sin6_addr_s6_addr=yes],
+                    [my_member_sockaddr_in6_sin6_addr_s6_addr=no],
+                    [[#include <netinet/in.h>]])
+    if test "x$my_cv_func_in6_is_addr_v4mapped$my_member_sockaddr_in6_sin6_addr_s6_addr" = xyesyes; then
+       AC_DEFINE([HAVE_WORKING_IN6_IS_ADDR_V4MAPPED], [1],
+                 [Define if you have a working IN6_IS_ADDR_V4MAPPED()])
+    fi
+])