tests/color_util: expose color_float_apply_curve()

I will be needing this in color-icc-output blending test.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/color_util.c

@@ -257,7 +257,7 @@ a8r8g8b8_to_float(uint32_t v)
 	return cf;
 }
 
-static struct color_float
+struct color_float
 color_float_apply_curve(enum transfer_fn fn, struct color_float c)
 {
 	unsigned i;

tests/color_util.h

@@ -111,6 +111,9 @@ process_pixel_using_pipeline(enum transfer_fn pre_curve,
 struct color_float
 color_float_unpremult(struct color_float in);
 
+struct color_float
+color_float_apply_curve(enum transfer_fn fn, struct color_float c);
+
 struct color_float
 color_float_apply_matrix(const struct lcmsMAT3 *mat, struct color_float c);