Re: [PATCH dwarves v2] Respect CMAKE_INSTALL_LIBDIR

[Alan Maguire <alan.maguire@oracle.com>]

On 25/11/2024 18:47, Ben Olson wrote:
> This patch changes the `cmake` configuration to honor `CMAKE_INSTALL_LIBDIR`
> and use either `lib` or `lib64` by default so that installations match the
> conventional placement of libraries.
> For example, it will now install `libdwarves.so` into `${PREFIX}/lib` or
> `${PREFIX}/lib64`, depending on the distribution.
> 
> Signed-off-by: Brandon Kammerdiener <brandon.kammerdiener@intel.com>
> Signed-off-by: Ben Olson <matthew.olson@intel.com>
> Cc: Alan Maguire <alan.maguire@oracle.com>

Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>

(tested on Oracle Linux which uses lib64 for libraries; specifying cmake
with no arguments did the right thing and "make install" installed into
/usr/local/lib64 as expected; nice!)

One small nit I noticed, sorry missed this last time - the README
has another reference to -D__LIB:

"    Ex. cmake -D__LIB=lib -DBUILD_SHARED_LIBS=OFF .."

I think we should probably remove that reference also, right?

> ---
> 
> Changes in v2:
>   - Included the proper built-in CMake module
>   - Made commit message distro-agnostic
> 
>  CMakeLists.txt | 19 ++++++-------------
>  README         |  3 +--
>  2 files changed, 7 insertions(+), 15 deletions(-)
> 
> diff --git a/CMakeLists.txt b/CMakeLists.txt
> index 8ca1bf2..1d0dadf 100644
> --- a/CMakeLists.txt
> +++ b/CMakeLists.txt
> @@ -21,18 +21,9 @@ else()
>  	LINK_DIRECTORIES(${LIBBPF_LIBRARY_DIRS})
>  endif()
>  
> -# Try to parse this later, Helio just showed me a KDE4 example to support
> -# x86-64 builds.
> -# the following are directories where stuff will be installed to
> -set(__LIB "" CACHE STRING "Define suffix of directory name (32/64)" )
> -
> -macro(_set_fancy _var _value _comment)
> -	if (NOT DEFINED ${_var})
> -		set(${_var} ${_value})
> -	else (NOT DEFINED ${_var})
> -		set(${_var} "${${_var}}" CACHE PATH "${_comment}")
> -	endif (NOT DEFINED ${_var})
> -endmacro(_set_fancy)
> +# Use the standard library installation directory
> +include(GNUInstallDirs)
> +set(CMAKE_INSTALL_LIBDIR "lib" CACHE STRING "libdir name")
>  
>  # where to look first for cmake modules,
>  # before ${CMAKE_ROOT}/Modules/ is checked
> @@ -84,7 +75,9 @@ if(NOT LIBBPF_FOUND AND NOT EXISTS "${PROJECT_SOURCE_DIR}/lib/bpf/src/btf.h")
>  	message(FATAL_ERROR "The submodules were not downloaded! GIT_SUBMODULE was turned off or failed. Please update submodules and try again.")
>  endif()
>  
> -_set_fancy(LIB_INSTALL_DIR "${EXEC_INSTALL_PREFIX}${CMAKE_INSTALL_PREFIX}/${__LIB}" "libdir")
> +if (NOT DEFINED LIB_INSTALL_DIR)
> +    set(LIB_INSTALL_DIR "${EXEC_INSTALL_PREFIX}${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
> +endif()
>  
>  # libbpf uses reallocarray, which is not available in all versions of glibc
>  # libbpf's include/tools/libc_compat.h provides implementation, but needs
> diff --git a/README b/README
> index f9aeef7..0627872 100644
> --- a/README
> +++ b/README
> @@ -3,8 +3,7 @@ Build instructions:
>  1. install cmake
>  2. mkdir build
>  3. cd build
> -4. cmake -D__LIB=lib ..
> -5. make install
> +4. make install
>  
>  cmake Options:
>    -DBUILD_SHARED_LIBS