sync code with last improvements from OpenBSD

lib/xcb-util-xrm/m4/xcb_util_m4_with_include_path.m4

@@ -0,0 +1,24 @@
+# XCB_UTIL_M4_WITH_INCLUDE_PATH
+# ------------------------------
+#
+# This macro attempts to locate an m4 macro processor which supports
+# -I option and is only useful for modules relying on M4 in order to
+# expand macros in source code files.
+#
+# M4: variable holding the path to an usable m4 program.
+#
+# This macro  requires Autoconf 2.62  or later  as it is  relying upon
+# AC_PATH_PROGS_FEATURE_CHECK  macro. NOTE:  As  soon  as the  minimum
+# required version of Autoconf for Xorg  is bumped to 2.62, this macro
+# is supposed to be shipped with xorg/util/macros.
+#
+AC_DEFUN([XCB_UTIL_M4_WITH_INCLUDE_PATH], [
+AC_CACHE_CHECK([for m4 that supports -I option], [ac_cv_path_M4],
+   [AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4],
+       [[$ac_path_M4 -I. /dev/null > /dev/null 2>&1 && \
+         ac_cv_path_M4=$ac_path_M4 ac_path_M4_found=:]],
+   [AC_MSG_ERROR([could not find m4 that supports -I option])],
+   [$PATH:/usr/gnu/bin])])
+
+AC_SUBST([M4], [$ac_cv_path_M4])
+]) # XCB_UTIL_M4_WITH_INCLUDE_PATH