only including intl headers while compiling libgtop.

* include/glibtop/global.h: only including intl headers
while compiling libgtop.

include/glibtop/global.h

@@ -55,11 +55,13 @@
 #include <guile/gh.h>
 #endif
 
+#ifdef _IN_LIBGTOP
 #if (defined HAVE_LIBINTL_H) || (defined HAVE_GETTEXT)
 #include <libintl.h>
 #else
 #include <libgettext.h>
 #endif
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>