[libgimp,app] add missing includes for windows

app/core/gimpdatafactory.c

@@ -22,6 +22,7 @@
 
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <gegl.h>
+#include <stdlib.h>
 
 #include "libgimpbase/gimpbase.h"
 #include "libgimpmath/gimpmath.h"

app/display/gimpdisplayshell.c

@@ -18,6 +18,7 @@
 #include "config.h"
 
 #include <string.h>
+#include <stdlib.h>
 
 #include <gegl.h>
 #include <gtk/gtk.h>

libgimp/gimp-debug.c

@@ -50,6 +50,7 @@
 
 #  include <windows.h>
 #  include <tlhelp32.h>
+#  include <process.h>
 #  undef RGB
 #endif