If the port requires gettext, set USES= gettext, and the port will inherit a dependency on libintl.so from devel/gettext. Other values for gettext usage are listed in USES=gettext.

A rather common case is a port using gettext and configure. Generally, GNU configure should be able to locate gettext automatically.

USES=	gettext
GNU_CONFIGURE=	yes

If it ever fails to, hints at the location of gettext can be passed in CPPFLAGS and LDFLAGS using localbase as follows:

USES=	gettext localbase:ldflags
GNU_CONFIGURE=	yes

Some software products allow for disabling NLS. For example, through passing --disable-nls to configure. In that case, the port must use gettext conditionally, depending on the status of the NLS option. For ports of low to medium complexity, use this idiom:

GNU_CONFIGURE=		yes

OPTIONS_DEFINE=		NLS
OPTIONS_SUB=		yes

NLS_USES=		gettext
NLS_CONFIGURE_ENABLE=	nls

.include <bsd.port.mk>

Or using the older way of using options:

GNU_CONFIGURE=		yes

OPTIONS_DEFINE=		NLS

.include <bsd.port.options.mk>

.if ${PORT_OPTIONS:MNLS}
USES+=			gettext
PLIST_SUB+=		NLS=""
.else
CONFIGURE_ARGS+=	--disable-nls
PLIST_SUB+=		NLS="@comment "
.endif

.include <bsd.port.mk>

The next item on the to-do list is to arrange so that the message catalog files are included in the packing list conditionally. The Makefile part of this task is already provided by the idiom. It is explained in the section on advanced pkg-plist practices. In a nutshell, each occurrence of %%NLS%% in pkg-plist will be replaced by “@comment ” if NLS is disabled, or by a null string if NLS is enabled. Consequently, the lines prefixed by %%NLS%% will become mere comments in the final packing list if NLS is off; otherwise the prefix will be just left out. Then insert %%NLS%% before each path to a message catalog file in pkg-plist. For example:

%%NLS%%share/locale/fr/LC_MESSAGES/foobar.mo
%%NLS%%share/locale/no/LC_MESSAGES/foobar.mo

In high complexity cases, more advanced techniques may be needed, such as dynamic packing list generation.

There is a point to note about installing message catalog files. The target directories for them, which reside under LOCALBASE/share/locale, must not be created and removed by a port. The most popular languages have their respective directories listed in PORTSDIR/Templates/BSD.local.dist. The directories for many other languages are governed by the devel/gettext port. Consult its pkg-plist and see whether the port is going to install a message catalog file for a unique language.