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 lcms2-2.9.orig/lcms2.pc.in lcms2-2.9/lcms2.pc.in
--- lcms2-2.9.orig/lcms2.pc.in	2017-12-04 16:39:09.491042791 -0500
+++ lcms2-2.9/lcms2.pc.in	2017-12-04 16:40:58.941757920 -0500
@@ -7,5 +7,6 @@
 Description: LCMS Color Management Library
 Version: @VERSION@
 Libs: -L${libdir} -llcms2
-Libs.private: @LIB_MATH@ @LIB_THREAD@
+Libs.private: -ljpeg @LIB_MATH@ @LIB_THREAD@
 Cflags: -I${includedir}
+Requires: libtiff-4