Returns the path to the saga_cmd executable.
search_saga()
The path to installed saga_cmd binary.
On Microsoft Windows, automatic searching will occur first in 'C:/Program Files/SAGA-GIS'; 'C:/Program Files (x86)/SAGA-GIS'; 'C:/SAGA-GIS'; 'C:/OSGeo4W'; and 'C:/OSGeo4W64'.
On Linux, saga_cmd is usually included in PATH, if not an automatic search is performed in the '/usr/' folder.
For macOS, since version 8.5, SAGA-GIS is available as an standalone macOS app from SourceForge. The 'SAGA.app' package is searched first (assuming that it is installed in the '/Applications/' folder). Other macOS locations that are searched include '/usr/local/bin/' (for Homebrew installations) and within the QGIS application (SAGA-GIS is bundled with the QGIS application on macOS by default).
If multiple versions of SAGA-GIS are installed on the system, the path to the newest version is returned.