The EXTRA_DIST variable in a
Makefile.am lists files to be
included in the distribution (tarball). Most important
files are automatically included; for example, all files
listed as source files for binaries or libraries.
However, automake does not
know about .desktop files,
or SGML documentation; so these files must be listed in
EXTRA_DIST. make distcheck's attempt to build the
distribution will normally fail if you leave files out of
EXTRA_DIST.
