RGB / RGBA parsing / formatting.
Install with clib:
$ clib install clibs/rgba
typedef struct {
double r, g, b, a;
} rgba_t;
rgba_t
rgba_new(uint32_t rgba);
uint32_t
rgba_from_string(const char *str, short *ok);
void
rgba_to_string(rgba_t rgba, char *buf, size_t len);
void
rgba_inspect(uint32_t rgba);