SL-10449: Add dumping of shader to log file

indra/llrender/llshadermgr.cpp

@@ -569,12 +569,18 @@ static std::string get_object_log(GLhandleARB ret)
 
 //dump shader source for debugging
 void LLShaderMgr::dumpShaderSource(U32 shader_code_count, GLcharARB** shader_code_text)
-{	
+{
+	char num_str[16]; // U32 = max 10 digits
+
+	LL_SHADER_LOADING_WARNS() << "\n";
+
 	for (U32 i = 0; i < shader_code_count; i++)
 	{
-		fprintf(stderr, "%4d: %s", i+1, shader_code_text[i]);
+		snprintf(num_str, sizeof(num_str), "%4d: ", i+1);
+		std::string line_number(num_str);
+		LL_CONT << line_number << shader_code_text[i];
 	}
-    LL_SHADER_LOADING_WARNS() << LL_ENDL;
+    LL_CONT << LL_ENDL;
 }
 
 void LLShaderMgr::dumpObjectLog(GLhandleARB ret, BOOL warns, const std::string& filename)