Metal: Fix EEVEE-Next shader compilation errors

source/blender/draw/intern/shaders/common_debug_print_lib.glsl

@@ -202,6 +202,8 @@ void drw_print_value(int value)
   drw_print_value_uint(uint(abs(value)), false, (value < 0), false);
 }
 
+#ifndef GPU_METAL
+
 void drw_print_value(bool value)
 {
   if (value) {
@@ -212,6 +214,8 @@ void drw_print_value(bool value)
   }
 }
 
+#endif
+
 /* NOTE(@fclem): This is homebrew and might not be 100% accurate (accuracy has
  * not been tested and might dependent on compiler implementation). If unsure,
  * use drw_print_value_hex and transcribe the value manually with another tool. */