fix examples for unpolluted libctru headers

examples/gpu/source/main.c

@@ -9,6 +9,7 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <math.h>
 #include <3ds.h>
 

examples/http/source/main.c

@@ -1,3 +1,6 @@
+#include <stdlib.h>
+#include <string.h>
+
 #include <3ds.h>
 
 Result http_download(httpcContext *context)//This error handling needs updated with proper text printing once ctrulib itself supports that.

examples/mvd/source/main.c

@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <string.h>
+
 #include <3ds.h>
 
 #include "costable.h"

examples/sdmc/source/main.c

@@ -5,6 +5,7 @@
 //this example shows you how to load a binary image file from the SD card and display it on the lower screen
 //for this to work you should copy test.bin to the root of your SD card
 //this file was generated with GIMP by saving a 240x320 image to raw RGB
+#include <string.h>
 
 #include <3ds.h>
 #include "costable.h"

template/source/main.c

@@ -1,3 +1,5 @@
+#include <string.h>
+
 #include <3ds.h>
 
 int main()