--- config.h.in.orig	2016-10-31 02:56:33.475370000 +0100
+++ config.h.in	2016-10-31 02:56:52.037696000 +0100
@@ -918,7 +918,7 @@
    for clang but remains for g++; see <http://trac.macports.org/ticket/41033>.
    Assume DragonFly and FreeBSD will be similar.  */
 #if (((defined __APPLE__ && defined __MACH__) \
-      || defined __DragonFly__ || defined __FreeBSD__) \
+      || defined __BSDSUniX__ || defined __DragonFly__ || defined __FreeBSD__) \
      && (defined __header_inline \
          ? (defined __cplusplus && defined __GNUC_STDC_INLINE__ \
             && ! defined __clang__) \