59d5f692f removed cmake.deps/cmake/DownloadAndExtractFile.cmake and
support for USE_EXISTING_SRC_DIR. The Ubuntu nightly PPA still relies
on USE_EXISTING_SRC_DIR functionality since it can't access the network
during the build.
Supplying an empty value for ExternalProject_Add()'s URL value appears
to provide the needed mechanism to avoid re-downloading when the sources
are already present. This is undocumented behavior, though, so it may
break in the future.
Now, if USE_EXISTING_SRC_DIR is set, the ExternalProject's URL variable
is unset, preventing the download and erroring out if the source doesn't
actually exist.
DownloadAndExtractFile.cmake was initially introduced as a workaround to
avoid the massive amounts of logs generated by the download progress.
This is not a problem anymore as ExternalProject_Add has had the
DOWNLOAD_NO_PROGRESS option since cmake version 3.1.
Change the default build type to always be Debug, and allow only four
predefined build types: Debug, Release, RelWithDebInfo and MinRelSize.
Furthermore, flags meant for single-configuration generator (make,
ninja) will not be used for multi-configuration generators (visual
studio, Xcode), and flags meant for multi-configuration generators will
not be used for single-configuration generators.
This will allow Debug builds to be built with MSVC which requires that
all dependencies are also built with the Debug build type to avoid
runtime library mismatch.
The correct way to specify build type (for example Release) for
single-configuration generators (Make and Ninja) is to run
cmake -B build -D CMAKE_BUILD_TYPE=Release
cmake --build build
while for multi-configuration generators (Visual Studio, Xcode and Ninja
Multi-Config) is to run
cmake -B build
cmake --build build --config Release
Passing CMAKE_BUILD_TYPE for multi-config generators will now not only
not be used, but also generate a warning for the user.
Co-authored-by: dundargoc <gocundar@gmail.com>
Problem:
Dirs "config", "packaging", and "third-party" are all closely related
but this is not obvious from the layout. This adds friction for new
contributors.
Solution:
- rename config/ to cmake.config/
- rename test/config/ to test/cmakeconfig/ because it is used in Lua
tests: require('test.cmakeconfig.paths').
- rename packaging/ to cmake.packaging/
- rename third-party/ to cmake.deps/ (parallel with .deps/)
