Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -198,10 +198,16 @@
 	CPPFLAGS="-D_GNU_SOURCE $CPPFLAGS"
 	AC_MSG_RESULT(yes)
 ], [
 	AC_MSG_RESULT(no)
 ])
+
+case "$host_os" in
+	solaris*)
+		CPPFLAGS="-D__EXTENSIONS__ -D_POSIX_PTHREAD_SEMANTICS $CPPFLAGS"
+		;;
+esac
 
 objc_runtime="ObjFW runtime"
 AC_CHECK_HEADER(objc/objc.h)
 AC_MSG_CHECKING(which Objective C runtime to use)
 AC_ARG_ENABLE(runtime,