use top_srcdir, top_builddir, abs_top_srcdir or abs_top_builddir only if needed The build system runs primarily in the top-level directory now, so unless a Make rule changes the working directory before referencing a file, it is not necessary to use the abs_top_X or top_X directory names. * Makefile.am, build-aux/common.mk, doc/module.mk, libgui/graphics/module.mk, libgui/module.mk, libgui/src/module.mk, libinterp/corefcn/module.mk, libinterp/module.mk, liboctave/cruft/module.mk, liboctave/cruft/ranlib/module.mk, liboctave/module.mk, liboctave/numeric/module.mk liboctave/operators/module.mk, scripts/module.mk, src/module.mk: Only use Use $(top_srcdir), $(top_builddir), $(abs_top_srcdir), and $(abs_top_builddir) if necessary.

--- a/liboctave/operators/module.mk	Wed Feb 17 11:35:42 2016 -0500
+++ b/liboctave/operators/module.mk	Wed Feb 17 13:32:44 2016 -0500
@@ -57,7 +57,7 @@
 
 ## Special rules for sources which must be built before rest of compilation.
 
-OP_SRCDIR = $(abs_top_srcdir)/liboctave/operators
+OP_SRCDIR = $(srcdir)/liboctave/operators
 
 define run-mk-ops
   rm -f $@-t $@ && \