Add cmake build system

[mtaillefumier]

This pr contains a minimal version of the cmake build system. It compiles the library and generate all necessary config files for use in other cmake and pkg-config projects. It should make the library detection in tmlQCD easier.

NB: there is no changes to the original build system.

• config files for cmake and pkg-config
• reformatting
• add ctests

[kostrzewa]

@kottnad @chaoos in preparation for the discussion it would be great if you could take a look at this

[kostrzewa]

@mtaillefumier thanks, this seems to work according to initial tests. It's just not yet installing the two binaries lemon_benchmark and lemon_contents into a bin directory in the install prefix.

[kostrzewa]

The other thing we should discuss is if we would not prefer to have the library as a static library. Usually we do static libraries to avoid confusion when multiple versions of the same library are around.

[mtaillefumier]

We can solve this with CMAKE_BUILD_SHARED OFF by default. I will make the necessary changes

[mtaillefumier]

Update:

• install lemon_benchmark and lemon_contents
• Build the static library by default (with fpic)

[chaoos]

I can build, but not install. It fails to install lemon_contents with:

$ cmake -S . -B build -DCMAKE_INSTALL_PREFIX=./install_dir
...
$ cmake --build build -j
...
$ cmake --install build
-- Install configuration: ""
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/cmake/clemon/ClemonConfig.cmake
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/cmake/clemon/ClemonConfigVersion.cmake
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/pkgconfig/clemon.pc
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/liblemon.so
-- Set non-toolchain portion of runtime path of "/home/roman/projects/tmp/lemon/install_dir/lib/liblemon.so" to ""
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/cmake/clemon/ClemonTargets.cmake
-- Installing: /home/roman/projects/tmp/lemon/install_dir/lib/cmake/clemon/ClemonTargets-noconfig.cmake
CMake Error at build/cmake_install.cmake:103 (file):
  file INSTALL cannot find "/home/roman/projects/tmp/lemon/lemon_contents":
  No such file or directory.

It does work if the build directory is equal to the source directory though, ie.

cmake -S . -DCMAKE_INSTALL_PREFIX=./install_dir
cmake --build . -j
cmake --install .

works!

[chaoos]

With the BUILD_SHARED_LIBS variable this should now be:

Suggested change

	add_library(lemon SHARED ${LEMON_SRCS})
	add_library(lemon ${LEMON_SRCS})

Else you always get shared libs.

[kottnad]

Trying to install on e.g. juwels booster still fails for me, i.e. does not move the binaries to the separate install directory :

CMake Error at cmake_install.cmake:99 (file): file INSTALL cannot find "/p/home/jusers/ottnad1/juwels/source/lemon/lemon_contents": No such file or directory.

(lemon_contents and lemon_benchmark are located in the build not the source directory.)