libintl.h compile failure on OSX

[Brian Aker]

depbase=`echo mktime.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
 /bin/sh ../libtool --tag=CC --mode=compile gcc -std=gnu99 -DHAVE_CONFIG_H -I.. -I.. -isystem ../gnulib -isystem ../gnulib -ggdb3 -I/usr/local/include -isystem /usr/local/include -D_THREAD_SAFE -pipe -O3 -Werror -pedantic -Wall -Wundef -Wshadow -fdiagnostics-show-option -Wformat -fno-strict-aliasing -Wno-strict-aliasing -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wredundant-decls -Wmissing-declarations -Wcast-align -MT mktime.lo -MD -MP -MF $depbase.Tpo -c -o mktime.lo mktime.c &&\
 mv -f $depbase.Tpo $depbase.Plo
In file included from getopt.c:36:
gettext.h:25:22: error: libintl.h: No such file or directory
cc1: warnings being treated as errors
In file included from getopt.c:36:
gettext.h: In function ‘pgettext_aux’:
gettext.h:146: warning: implicit declaration of function ‘dcgettext’
gettext.h:146: warning: incompatible implicit declaration of built-in function ‘dcgettext’
gettext.h: In function ‘npgettext_aux’: