Added common folder, with a new string helper file.

Makefile

@@ -19,7 +19,7 @@ include $(DEVKITARM)/3ds_rules
 #---------------------------------------------------------------------------------
 export TARGET		:=	$(shell basename $(CURDIR))
 BUILD		:=	build
-SOURCES		:=	source source/tests source/tests/fs source/tests/cpu
+SOURCES		:=	source source/common source/tests source/tests/fs source/tests/cpu
 DATA		:=	data
 INCLUDES	:=	source #include
 

source/common/string_funcs.cpp

@@ -0,0 +1,25 @@
+#include "string_funcs.h"
+
+#include <cstdarg>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+namespace Common {
+
+std::string FormatString(const char* format, ...)
+{
+    va_list arguments;
+    char *va_str;
+
+    va_start(arguments, format);
+    vasprintf(&va_str, format, arguments);
+    va_end(arguments);
+
+    std::string out_str(va_str);
+    free(va_str);
+    
+    return out_str;
+}
+
+}

source/common/string_funcs.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <string>
+
+namespace Common {
+
+std::string FormatString(const char* format, ...);
+
+}

source/tests/fs/fs_sdmc.cpp

@@ -2,7 +2,7 @@
 #include <cstring>
 #include <3ds.h>
 
-#include "scope_exit.h"
+#include "common/scope_exit.h"
 #include "tests/test.h"
 #include "tests/fs/fs_sdmc.h"