This program verifies the libpng source tree, expecting consistent
definitions of version numbers in the C source code, in the Autoconf
scripts, and in the CMake scripts.
The version verification is performed as follows. (Please note that
the version definitions in png.h are checked twice.)
* The files png.h, configure.ac and CMakeLists.txt are checked by
the ci_verify_version.sh program.
* The files png.h, png.c and pngtest.c are checked by the pngtest
program.
