#include <fontconfig/fontconfig.h> void FcConfigSetSysRoot (FcConfig *config, const FcChar8 *sysroot);
Set 'sysroot' as the system root directory. All file paths used or created with this 'config' (including file properties in patterns) will be considered or made relative to this 'sysroot'. This allows a host to generate caches for targets at build time. This also allows a cache to be re-targeted to a different base directory if 'FcConfigGetSysRoot' is used to resolve file paths. When setting this on the current config this causes changing current config (calls FcConfigSetCurrent()).