The tarball distribution includes the output of the Automake and Autoconf tools (the Makefile.in and configure.sh files, respectively), while building from a VC

The tarball distribution includes the output of the Automake and Autoconf tools (the Makefile.in and configure.sh files, respectively), while building from a VCS checkout does not. Thus, building from a checkout requires extra steps and software that you may not already have ready to hand.