Building GnuPG from the GIT repositories

Note that this is only for developers and there is no guarantee that a version will work.

In general follow the instructions in the README.GIT files
You may not use the latest automake version because they have a regression against former versions. README.GIT gives hints on how to use older versions.
Here is a script to build GnuPG and all its related libraries: https://github.com/Wikinaut/utils/wiki#wiki-How_to_compile_GnuPG_gpg_from_the_github_sources

Building using speedo.mk

Assuming you have all the tools required installed. (On debian you can probably just do an apt-get build-dep gnupg2)

Example with build dir /tmp/gnupg-build and install dir /tmp/gnupg-install change this like you want. And add it to PATH / LD_LIBRARY PATH as needed.

BUILDD=/tmp/gnupg-build
mkdir $BUILDD
cd $BUILDD
git clone git:https://git.gnupg.org/gnupg
cd gnupg
./autogen.sh
make -f build-aux/speedo.mk gitrep=git:https://git.gnupg.org SELFCHECK=0 INSTALL_PREFIX=/tmp/gnupg-install  git-native