CMake Makefile generators silently ignore missing CMakeLists.txt files
and just treat the source directory as if it had an empty input file.
This will be addressed with a new CMake Policy, but for now we make the
VS generator consistent with the Makefile generator behavior. The VS
generator will need to handle the OLD behavior of the policy anyway.
The cmGlobalGenerator::AddTargetDepends method traces the dependencies
of targets recursively to collect the complete set of targets needed for
a given project (for VS .sln files). This commit teaches the method to
avoid tracing its dependencies more than once. Otherwise the code does
an all-paths walk needlessly.
We define the export(PACKAGE) command mode to store the location of the
build tree in the user package registry. This will help find_package
locate the package in the build tree. It simplies user workflow for
manually building a series of dependent projects.
A common user workflow is to build a series of dependent projects in
order. Each project locates its dependencies with find_package. We
introduce a "user package registry" to help find_package locate packages
built in non-standard search locations.
The registry explicitly stores locations of build trees providing
instances of a given package. There is no defined order among the
locations specified. These locations should provide package
configuration files (<package>-config.cmake) and package version files
(<package>-config-version.cmake) so that find_package will recognize the
packages and test version numbers.
We create target property "LINK_INTERFACE_MULTIPLICITY" and a per-config
version "LINK_INTERFACE_MULTIPLICITY_<CONFIG>". It sets the number of
times a linker should scan through a mutually dependent group of static
libraries. The largest value of this property on any target in the
group is used. This will help projects link even for extreme cases of
cyclic inter-target dependencies.
The 'binary' openmode does not exist on all compilers. We define macro
<kwsys>_ios_binary, where <kwsys> is the KWSys namespace, to refer to
std::ios::binary if it exists and 0 otherwise. Sample usage:
kwsys_ios::ifstream fin(fn, kwsys_ios::ios::in | kwsys_ios_binary);
In cmComputeLinkInformation::Compute we add implicit link information
from languages other than the linker language to the end of the link
line. This factors out that code into separate methods to improve
readability and organization.