This creates new module ExternalProject.cmake to replace the prototype
AddExternalProject.cmake module. The interface is more refined, more
flexible, and better documented than the prototype.
This also converts the ExternalProject test to use the new module. The
old module will be removed (it was never in a CMake release) after
projects using it have been converted to the new module.
The add_external_project function separates its arguments with ';'
separators, so previously no command line argument could contain one.
When specifying CMAKE_ARGS, some -D argument values may need to contain
a semicolon to form lists in the external project cache.
This adds add_external_project argument LIST_SEPARATOR to specify a list
separator string. The separator is replaced by ';' in arguments to any
command created to drive the external project. For example:
add_external_project(...
LIST_SEPARATOR ::
CMAKE_ARGS -DSOME_LIST:STRING=A::B::C
...)
passes "-DSOME_LIST:STRING=A;B;C" to CMake for the external project.
This creates function 'add_external_project_step' to centralize creation
of external project steps. Users may call it to add custom steps to
external project builds.
The patch step runs parallel to the update step since it does not make
sense to have both. Configuration of the step requires specification of
a PATCH_COMMAND argument to add_external_project.
This rewrites the keyword/argument parsing and handling in the
AddExternalProject module to use arguments more literally:
- The strict keyword-value pairing is gone in favor of keywords with
arbitrary non-keyword values. This avoids requiring users to escape
spaces and quotes in command lines.
- Customized step command lines are now specified with a single
keyword <step>_COMMAND instead of putting the arguments in a
separate entry (previously called <step>_ARGS).
- Build step custom commands now use VERBATIM mode so that arguments
are correctly escaped on the command line during builds.
This teaches AddExternalProject to run "$(MAKE)" for build and install
steps of CMake-based external projects when using a Makefile generator.
It allows the external project to participate in a parallel make invoked
on the superproject.
David Cole
Brad King