This marks all `<PACKAGENAME>_FOUND` result variables as deprecated
where possible (for `<PackageName>` find modules) to make it clearer
which variable to use.
In CMake 3.3, the FindPackageHandleStandardArgs module was refactored to
set both `<PackageName>_FOUND` and uppercase `<PACKAGENAME>_FOUND`
result variables to the same values. Before that, the FOUND_VAR argument
could be used to set the result variable.
* FindMatlab: Uppercased MATLAB_FOUND is not mentioned as it was never
documented.
* Documentation for FindPythonInterp and FindPythonLibs modules synced
accordingly to their deprecation (3.12 instead of 4.2).
* OPENGL_FOUND: deprecation version synced with other find modules.
* DevIL_FOUND was introduced in CMake 3.8. The uppercased variant not
mentioned as it was previously never documented.
Fixes: #27242
Since most of the find modules use the `<PackageName>_FOUND` result
variables, this now also syncs it for the FindPkgConfig module. The
`PkgConfig_FOUND` result variable is available since CMake 3.3 and
contains the same value. There is also `PKGCONFIG_FOUND` result variable
automatically set with the same value but for simplicity isn't
documented. The uppercased `<PACKAGENAME>_FOUND` result variables set by
find modules are also considered legacy variables.
- Added intro code blocks showing how to use find modules.
- Synced modules documentation.
- Extended few examples to make the intro code blocks fit into the
modules descriptions.
- Synced some RST formatting, variables descriptions and positions.
- Removed few redundant internal comments.
Issue: #26555
The `find_package_handle_standard_args(FOUND_VAR)` is deprecated as of
CMake 3.3 and both the `<PackageName>_FOUND` and the upper-cased
`<PACKAGE_NAME>_FOUND` are set with or without using this option.
Additionally, find modules and docs are also synced with this to make it
clearer.
Before calling pkg_check_modules, modules must check PKG_CONFIG_FOUND.
When FindPkgConfig.cmake is loaded, pkg_check_modules is always defined
regardless of pkg-config being present. However, the whole module might
be disabled on user request with CMAKE_DISABLE_FIND_PACKAGE_PkgConfig.
This must not break Find modules which just look for a hint or similar.
Our documented standard for find module variable names is to match the
case of the find module package name. This was overlooked when the
module was added by commit 84e7920b3a (FindFontconfig: Add module to
find Fontconfig, 2018-09-27, v3.14.0-rc1~523^2).
The module was released with the upper case names in CMake 3.14.0, so
fix it to have camel case names in 3.14.1. This is incompatible but
anyone using a given release series should be using the latest patch on
it and we've made breaking fixups on newly released features like this
before.
Reported-by: Christophe Giboudeaux <christophe@krop.fr>
Fixes: #19094
Peter Kokot