Some packages, notably GNU GCC and GNU gdb, have a build environment originally written at Cygnus Support (subsequently renamed Cygnus Solutions, and then later purchased by Red Hat). Packages with this ancestry are sometimes referred to as "Cygnus" trees.
A Cygnus tree has slightly different rules for how a
is to be constructed. Passing
cause any generated
Makefile.in to comply with Cygnus rules.
Here are the precise effects of
texinfo.texis not required if a Texinfo source file is specified. The assumption is that the file will be supplied, but in a place that Automake cannot find. This assumption is an artifact of how Cygnus packages are typically bundled.
make distis not supported, and the rules for it are not generated. Cygnus-style trees use their own distribution mechanism.
PATH. These tools are
checktarget doesn't depend on
GNU maintainers are advised to use
gnu strictness in preference
to the special Cygnus mode. Some day, perhaps, the differences between
Cygnus trees and GNU trees will disappear (for instance, as GCC is made
more standards compliant). At that time the special Cygnus mode will be