impellerCHelpSupportsDepfile function
Returns whether the impellerc --help text advertises --depfile.
Older impellerc builds either omit the flag entirely or accept it without
producing a depfile in --shader-bundle mode. Build hooks use this helper
to avoid passing an unsupported flag while preserving the existing manifest
dependency fallback.
Implementation
bool impellerCHelpSupportsDepfile(String helpText) {
return helpText.contains('--depfile=');
}