[graphics][compute] Properly export C functions for use in C++ (/color,/ts)

Tracked by SPN-19.

Testability: not yet part of build.
Change-Id: I04c73606b03191d2c6e4f2048f329af848c8f5fb

src/graphics/lib/compute/color/color.c

@@ -3,15 +3,11 @@
 // found in the LICENSE file.
 
 //
-//
+// COLOR UTILITIES
 //
 
-#include <math.h>
 #include "color.h"
-
-//
-// COLOR UTILITIES
-//
+#include <math.h>
 
 //
 // CONVERT FROM 0xAARRGGBB WORD ORDER INTO f32[4]

src/graphics/lib/compute/color/color.h

@@ -14,6 +14,14 @@
 
 #include <stdint.h>
 
+//
+//
+//
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 //
 // CONVERT FROM 0xAARRGGBB WORD ORDER INTO f32[4]
 //
@@ -63,3 +71,11 @@ void color_linear_lerp_rgba_f32(float       rgba_m[4],
 //
 //
 //
+
+#ifdef __cplusplus
+}
+#endif
+
+//
+//
+//

src/graphics/lib/compute/ts/transform_stack.h

@@ -18,6 +18,14 @@
 //
 //
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//
+//
+//
+
 struct ts_transform_stack;
 
 //
@@ -249,3 +257,11 @@ ts_transform_stack_multiply(struct ts_transform_stack * const ts);
 //
 //
 //
+
+#ifdef __cplusplus
+}
+#endif
+
+//
+//
+//