Generator expressions are supported in many places and are a distinct
concept worthy of their own manual page. The old builtin documentation
was previously represented by preprocessor macros to generate it into
each place that supports them. Factor out the duplicate content into a
dedicated cmake-generator-expressions manual page and reference it from
each original location.
The COMPILE_DEFINITIONS escaping disclaimer was represented in builtin
documentation using a preprocessor macro. Factor the duplicate content
out into a separate .txt file and include it in each document with the
reStructuredText include directive.
Portions of these documents contain duplicate content generated from
preprocessor macros in the original builtin documentation source.
Factor the common parts out into .txt files using reStructuredText
include directives and substitutions to avoid duplication.
Brad King
Kitware Robot