The naming conflict with FindLibLZMA module gets worse.
Not avoiding it in the first place was stupid.
Normally find_package(LibLZMA) will use the module and
find_package(liblzma 5.2.5 REQUIRED CONFIG) will use the config
file even with a case insensitive file system. However, if
CMAKE_FIND_PACKAGE_PREFER_CONFIG is TRUE and the file system
is case insensitive, find_package(LibLZMA) will find our liblzma
config file instead of using FindLibLZMA module.
One big problem with this is that FindLibLZMA uses
LibLZMA::LibLZMA and we use liblzma::liblzma as the target
name. With target names CMake happens to be case sensitive.
To workaround this, this commit adds
add_library(LibLZMA::LibLZMA ALIAS liblzma::liblzma)
to the config file. Then both spellings work.
To make the behavior consistent between case sensitive and
insensitive file systems, the config and related files are
renamed from liblzmaConfig.cmake to liblzma-config.cmake style.
With this style CMake looks for lowercase version of the package
name so find_package(LiBLzmA 5.2.5 REQUIRED CONFIG) will work
to find our config file.
There are other differences between our config file and
FindLibLZMA so it's still possible that things break for
reasons other than the spelling of the target name. Hopefully
those situations aren't too common.
When the config file is available, it should always give as good or
better results as FindLibLZMA so this commit doesn't affect the
recommendation to use find_package(liblzma 5.2.5 REQUIRED CONFIG)
which explicitly avoids FindLibLZMA.
Thanks to Markus Rickert.
The syntax "if(DEFINED CACHE{FOO})" requires CMake 3.14.
In some other places the code treats the cache variables
like normal variables already (${FOO} or if(FOO) is used,
not ${CACHE{FOO}).
Thanks to ygrek for reporting the bug on IRC.
Seems that the phrase "add more quotes" from sh/bash scripting
applies to CMake as well. E.g. passing an unquoted list ${FOO}
to a function that expects one argument results in only the
first element of the list being passed as an argument and
the rest get ignored. Adding quotes helps ("${FOO}").
list(INSERT ...) is weird. Inserting an empty string to an empty
variable results in empty list, but inserting it to a non-empty
variable does insert an empty element to the list.
Since INSERT requires at least one element,
"${CMAKE_THREAD_LIBS_INIT}" needs to be quoted in CMakeLists.txt.
It might result in an empty element in the list. It seems to not
matter as empty elements consistently get ignored in that variable.
In fact, calling cmake_check_push_state() and cmake_check_pop_state()
will strip the empty elements from CMAKE_REQUIRED_LIBRARIES!
In addition to quoting fixes, this fixes checks for the cache
variables in tuklib_cpucores.cmake and tuklib_physmem.cmake.
Thanks to Martin Matuška for testing and reporting the problems.
These fixes aren't tested yet but hopefully they soon will be.
This does *NOT* replace the Autotools-based build system in
the foreseeable future. See the comment in the beginning
of CMakeLists.txt.
So far this has been tested only on GNU/Linux but I commit
it anyway to make it easier for others to test. Since I
haven't played much with CMake before, it's likely that
there are things that have been done in a silly or wrong
way and need to be fixed.
huangqinjin
Lasse Collin