Fix "Some translated strings are still in English" issue

ENABLE_NLS is always undefined in some files and
some translatable messages in these files are always displayed
in English. This commit fixes the issue.

src/config-ini.c

@@ -17,6 +17,9 @@
    Copyright (c) 2010  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>

src/gamma-drm.c

@@ -18,6 +18,10 @@
    Copyright (c) 2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>

src/gamma-dummy.c

@@ -17,6 +17,10 @@
    Copyright (c) 2013-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 

src/gamma-randr.c

@@ -17,6 +17,10 @@
    Copyright (c) 2010-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>

src/gamma-vidmode.c

@@ -17,6 +17,10 @@
    Copyright (c) 2010-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdint.h>

src/gamma-w32gdi.c

@@ -17,6 +17,10 @@
    Copyright (c) 2010-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 

src/location-geoclue2.c

@@ -17,6 +17,10 @@
    Copyright (c) 2014-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 

src/location-manual.c

@@ -17,6 +17,10 @@
    Copyright (c) 2010-2017  Jon Lund Steffensen <jonlst@gmail.com>
 */
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>