Add build rule for build-octave (bug #49503). * src/build-octave.mk: Add new build rule for build-octave which can be used for cross-building binary packages that depend on Octave as a build tool. * dist-files.mk: Add new file to list. * index.html: Add new package to list. * src/of-communications.mk, src/of-image.mk, src/of-mapping.mk, src/of-optiminterp.mk, src/of-sparsersb.mk, src/of-statistics.mk, src/of-windows.mk: Add optional dependency on build-octave. * configure.ac: Add new configure switch "--disable-system-octave" that is needed to build the build-octave package. * Makefile.in: Add variable "USE_SYSTEM_OCTAVE". Exclude build-octave from the default build tools and build it only if a package explicitly depends on it. Display warning about missing native Octave version only if necessary.

diff -ur libmng-2.0.2-orig/Makefile.am libmng-2.0.2/Makefile.am
--- libmng-2.0.2-orig/Makefile.am	2013-03-05 06:59:27 -0500
+++ libmng-2.0.2/Makefile.am	2013-11-09 12:13:37 -0500
@@ -9,6 +9,7 @@
 
 # libmng release @VERSION@
 libmng_la_LDFLAGS = \
+	-no-undefined \
 	-version-number @MNG_MAJOR_NR@:@MNG_MINOR_NR@:@MNG_RELEASE_NR@
 
 lib_LTLIBRARIES = libmng.la