ANDROID_NDK_NOSTDLIBPP_LDFLAG return -nostdlib++ or empty string if that flag is no required by Android NDK.

ANDROID_NDK_PLATFORM returns the Android API level to use in the building process.

ANDROID_NDK_REQUIRE_NOSTDLIBPP_LDFLAG returns true if the -nostdlib++ flag is required by Android NDK and false otherwise.

AppendToFlag is a quick function that appends content to a flag if is already defined.

TODO: export error.

TODO: export error.

MustGoPath returns the GOPATH that holds this package.

TODO: detect webkit support automatically.

TODO: export error.

TODO: export error.

TODO: use qmake props.

WalkFilterBlacklist filter out blacklisted file.

WalkFilterPrefix only process file that do not have specified prefix.

WalkFilterDirectory only allow directory.

WalkOnlyExtension only process file (not directory) that their extension is specified, without the `.` such as `go` or `html`.

WalkOnlyFile is opposite of WalkFilterDirectory, it only allow file.