You need to install Make. Most likely you do not have your operating system's toolchain installed. I believe for Mac OS X you need to install XCode, but there may be another way.
Git-specific note: You need to set your config.mak options. Notably, you should have NO_TCLTK=YesPlease if you don't have Tcl/Tk. Some other options may be necessary. Also if you don't have libcurl headers, use NO_CURL=YesPlease (WARNING: You won't be able to use http or https servers). If you do not have openssl headers, use NO_OPENSSL=YesPlease. And so on. Look in Makefile for more details.
According to the Makefile, since you are using Darwin, you need
NEEDS_CRYPTO_WITH_SSL=YesPlease
NEEDS_SSL_WITH_CRYPTO=YesPlease
NEEDS_LIBICONV=YesPlease
If you plan on using the test suite, NO_SVN_TESTS=YesPlease can speed up time to do so.
Consider enabling BLK_SHA1=YesPlease if applicable to Mac OS X. (not sure on this one)
gitdoes not use Autotools. It actually uses a handwritten Makefile and aconfig.mak.makeinstalled. XCode was probably the first thing I installed when I bought my mac, so I forgot thatmakedoesn't come with OS X by default.