Remove stray printfs.

SwiftShader shouldn't print anything to stdout in Release builds.

Also refactor UNIMPLEMENTED macro to be able to take a formatted string
with arguments.

Bug b/73656151

Change-Id: Ibadbfba3371324ba1bd608bd51bdac5e5923a20e
Reviewed-on: https://swiftshader-review.googlesource.com/21108
Reviewed-by: Merck Hung <merckhung@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/OpenGL/compiler/debug.cpp b/src/OpenGL/compiler/debug.cpp
index 61943a3..6517346 100644
--- a/src/OpenGL/compiler/debug.cpp
+++ b/src/OpenGL/compiler/debug.cpp
@@ -23,7 +23,7 @@
 #include "ParseHelper.h"
 
 #ifdef TRACE_ENABLED
-extern "C" {
+namespace sh {
 void Trace(const char *format, ...) {
 	if (!format) return;
 
@@ -39,6 +39,6 @@
 		parseContext->trace(buf);
 	}
 }
-}  // extern "C"
+}  // namespace sh
 #endif  // TRACE_ENABLED