FcConfigBuildFonts - Build font database
#include <fontconfig/fontconfig.h>
FcBool FcConfigBuildFonts (FcConfig *config);
Builds the set of available fonts for the given configuration. Note that any
  changes to the configuration after this call have indeterminate effects.
  Returns FcFalse if this operation runs out of memory. If config is
  NULL, the current configuration is used.