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 curl-7.33.0-orig/configure curl-7.33.0/configure
--- curl-7.33.0-orig/configure	2013-10-12 16:24:48 -0400
+++ curl-7.33.0/configure	2013-11-06 18:27:28 -0500
@@ -17798,7 +17798,7 @@
 
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-    as_fn_error $? "compiler does not halt on function prototype mismatch." "$LINENO" 5
+    #as_fn_error $? "compiler does not halt on function prototype mismatch." "$LINENO" 5
 
 else