http://www.gnu.org/software/gettext/FAQ.html#integrating_howto

# Add an invocation of AM_GNU_GETTEXT([external]) to the package's
  configure.{ac,in} file.  [DONE]

# Invoke \u201cgettextize --copy\u201d. It will do most of the
  autoconf/automake related work for you.  [DONE]

	Please add the files gettext.m4 iconv.m4 lib-ld.m4 lib-link.m4
	lib-prefix.m4 nls.m4 po.m4 progtest.m4 from the
	/usr/share/aclocal directory to your aclocal.m4 file.

	cat
	/usr/share/aclocal/{gettext.m4,iconv.m4,lib-ld.m4,lib-link.m4,lib-prefix.m4,nls.m4,po.m4,progtest.m4}
	>> aclocal.m4

# Add the gettext.h file to the package's source directory, and
  include it in all source files that contain translatable strings or
  do output via printf or fprintf.  [DONE]

# In the source file defining the main() function of the program, add
  these lines to the header

#include <locale.h>
#include "gettext.h"

and these lines near the beginning of the main() function:

setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);

[DONE]

# Mark all strings that should be translated with _(), like this:
  _("No errors found."). While doing this, try to turn the strings
  into good English, one entire sentence per string, not more than one
  paragraph per string, and use format strings instead of string
  concatenation. This is needed so that the translators can provide
  accurate translations.  [PARTLY DONE]

# In every source file containing translatable strings, add these
  lines to the header:

#include "gettext.h"
#define _(string) gettext (string)

# In the freshly created po/ directory, set up the POTFILES.in file,
  and do a \u201cmake update-po\u201d. Then distribute the generated
  .pot file to your nearest translation project.

[PARTLY DONE]

# Shortly before a release, integrate the translators' .po files into
  the po/ directory and do \u201cmake update-po\u201d again.
