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.

@echo off

REM Remove contents of cache directory including tmp and lock files (bug #45458)
del /Q /S %LOCALAPPDATA%\fontconfig\cache\ >nul 2>&1

set ROOT_DIR=%~dp0
if EXIST %ROOT_DIR%\mingw32\bin\octave-cli.exe set ROOT_DIR=%ROOT_DIR%\mingw32
if EXIST %ROOT_DIR%\mingw64\bin\octave-cli.exe set ROOT_DIR=%ROOT_DIR%\mingw64
echo "Updating fc-cache (may take a while) ..."
%ROOT_DIR%\bin\fc-cache.exe -v
echo "Done."