diff -up c-ares-1.10.0/ares_build.h.in.multilib c-ares-1.10.0/ares_build.h.in
--- c-ares-1.10.0/ares_build.h.in.multilib	2013-05-13 11:40:22.697814087 +0200
+++ c-ares-1.10.0/ares_build.h.in	2013-05-13 11:40:26.236813966 +0200
@@ -96,7 +96,14 @@
 #endif
 
 /* The size of `long', as computed by sizeof. */
-#undef CARES_SIZEOF_LONG
+#include <bits/wordsize.h>
+#if __WORDSIZE == 32
+#define CARES_SIZEOF_LONG 4
+#elif __WORDSIZE == 64
+#define CARES_SIZEOF_LONG 8
+#else
+#error "Unknown word size"
+#endif
 
 /* Integral data type used for ares_socklen_t. */
 #undef CARES_TYPEOF_ARES_SOCKLEN_T
diff -up c-ares-1.10.0/configure.ac.multilib c-ares-1.10.0/configure.ac
--- c-ares-1.10.0/configure.ac.multilib	2013-05-13 11:41:00.480812797 +0200
+++ c-ares-1.10.0/configure.ac	2013-05-13 11:41:17.210812226 +0200
@@ -457,7 +457,6 @@ AC_CHECK_SIZEOF(size_t)
 AC_CHECK_SIZEOF(long)
 AC_CHECK_SIZEOF(int)
 AC_CHECK_SIZEOF(short)
-CARES_CONFIGURE_LONG
 AC_CHECK_SIZEOF(time_t)
 
 AC_CHECK_TYPE(long long,