Support arch-specific lib and cmake folders with catkin_make_isolated

[scpeters]

In order to get into debian, they recommend using GNUInstallDirs for installing architecture-dependent libraries. For example, sdformat is in the process of this change, which on my machine causes libraries to be installed to {prefix}/lib/x86_64-linux-gnu/ and the cmake config file to be installed to {prefix}/lib/x86_64-linux-gnu/cmake/sdformat/.

There was some discussion about whether GNUInstallDirs should be used only for packaging debians or for all source installs. In the end, sdformat chose to use it always by default, and I think other packages may do the same. It would greatly enhance the utility of catkin_make_isolated to support this behavior, both for setting the CMAKE_PREFIX_PATH and for setting the LD_LIBRARY_PATH in the setup.sh scripts.

I had been using catkin_make_isolated to build sdformat and gazebo together by manually adding my own package.xml files. gazebo already uses GNUInstallDirs, so I have had to manually edit the LD_LIBRARY_PATH in setup.sh so that the gazebo binaries can find the gazebo libraries. Now with the sdformat change, gazebo cannot find_package sdformat because the cmake folder is in a subfolder of lib rather than share.

One clue for implementing this would be to parse the contents of /etc/ld.so.conf.d/:

$ cat /etc/ld.so.conf.d/x86_64-linux-gnu.conf 
# Multiarch support
/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu

[scpeters]

An alternative to parsing /etc/ld.so.conf.d/ is to include the GNUInstallDirs module in a sandbox to see if there are arch-specific lib folders for the given platform. An example CMakeLists.txt:

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
project (CMAKE_GNU_DIRS_TEST)
include(GNUInstallDirs)
message (STATUS "CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_LIBDIR}")

and its output on Ubuntu:

...
-- CMAKE_INSTALL_LIBDIR lib/x86_64-linux-gnu
...

[scpeters]

Note that this will be an issue for console_bridge when 0.2.5 is released (currently it's on 0.2.4).

This is when GNUInstallDirs was introduced into console_bridge, and it's listed as 0.2.5:
ros/console_bridge@3830f26

[scpeters]

I've been using a hardcoded workaround on my fork for the past week or so, and it's been successful. I just have to add the arch-specific folder to LD_LIBRARY_PATH and PKG_CONFIG_PATH. Now we just need to automatically identify the name of the arch-specific library folders.

@@ -498,11 +498,12 @@ def build_cmake_package(
     if new_setup_path != last_setup_env:
         subs = {}
         subs['cmake_prefix_path'] = install_target + ":"
-        subs['ld_path'] = os.path.join(install_target, 'lib') + ":"
+        subs['ld_path'] = os.path.join(install_target, 'lib') + ":" + \
+                          os.path.join(install_target, 'lib', 'x86_64-linux-gnu') + ":"
         pythonpath = os.path.join(install_target, get_python_install_dir())
         subs['pythonpath'] = pythonpath + ':'
-        subs['pkgcfg_path'] = os.path.join(install_target, 'lib', 'pkgconfig')
-        subs['pkgcfg_path'] += ":"
+        subs['pkgcfg_path'] = os.path.join(install_target, 'lib', 'pkgconfig') + ":" + \
+                              os.path.join(install_target, 'lib', 'x86_64-linux-gnu', 'pkgconfig') + ":"
         subs['path'] = os.path.join(install_target, 'bin') + ":"
         if not os.path.exists(os.path.dirname(new_setup_path)):
             os.mkdir(os.path.dirname(new_setup_path))

[scpeters]

So my previous testing only involved devel builds; I tried catkin_make_isolated --install and it didn't work. I made another hard-coded hack in scpeters@5597b58 that fixes install builds.