What is libintl.h and where can I get it?

FWIW on OSX with El Capitan and homebrew, I did a:

1) I wasn't sure if the El Capitan upgrade had broken something, so first I made sure I had the latest gettext:

$ brew reinstall gettext

Then I had to re-link by doing:

$ brew unlink gettext && brew link gettext --force

After that, other tools were able to find it, and life went back to normal.

I learned libintl comes from libgettext. If you already installed gettext by Homebrew, you would see:

$ locate libintl
/usr/local/Cellar/gettext/0.18.3.2/lib/libintl.8.dylib
/usr/local/Cellar/gettext/0.18.3.2/lib/libintl.a
/usr/local/Cellar/gettext/0.18.3.2/lib/libintl.dylib
<..snip..>

and the following works for me on the issue of "library not found for -lintl"

ln -s /usr/local/Cellar/gettext/0.18.3.2/lib/libintl.* /usr/local/lib/

Depending on the system, it's probably part of the GNU C library (glibc).

Note that just installing the file libintl.h isn't likely to do you any good.

On Debian-based systems (including Debian, Ubuntu, and Linux Mint), it's part of the libc6-dev package, installed with:

sudo apt-get install libc6-dev

Since you're using Mac OS X, a Google search for "libintl.h OSX" shows a lot of people having similar problems. According to the INSTALL file in the Git sources:

Set NO_GETTEXT to disable localization support and make Git only use English. Under autoconf the configure script will do this automatically if it can't find libintl on the system.

If you can find the proper version of Libtools (from http://ftp.gnu.org/gnu/libtool/) you might find it in the package..

Otherwise you can use below to the configure to remove this dependency:

./configure --disable-nls