Cleaning up CMakeLists to not rely on catkin_make crosstalk

[jbohren]

Fixes catkin/catkin_tools#210

This is the backtrace from master:

terminate called after throwing an instance of 'CGAL::Assertion_exception'
  what():  CGAL ERROR: assertion violation!
Expr: -CGAL_IA_MUL(-1.1, 10.1) != CGAL_IA_MUL(1.1, 10.1)
File: /usr/include/CGAL/Interval_nt.h
Line: 209
Explanation: Wrong rounding: did you forget the  -frounding-math  option if you use GCC (or  -fp-model strict  for Intel)?

Program received signal SIGABRT, Aborted.
0x00007ffff5b76cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
56  ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) where
#0  0x00007ffff5b76cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007ffff5b7a0d8 in __GI_abort () at abort.c:89
#2  0x00007ffff617b6b5 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00007ffff6179836 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4  0x00007ffff6179863 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5  0x00007ffff6179aa2 in __cxa_throw () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#6  0x00007ffff3ac6689 in CGAL::assertion_fail(char const*, char const*, int, char const*) () from /usr/lib/libCGAL.so.10
#7  0x00007ffff696ae2b in CGAL::Interval_nt<false>::Test_runtime_rounding_modes::Test_runtime_rounding_modes (this=0x7ffff6c7b048 <CGAL::Interval_nt<false>::tester>)
    at /usr/include/CGAL/Interval_nt.h:208
#8  0x00007ffff6964e80 in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /usr/include/CGAL/Interval_nt.h:223
#9  0x00007ffff6965013 in _GLOBAL__sub_I_ConditionCreator.cpp(void) () at /home/jbohren/ws/msl/src/cnc-msl/msl_expressions/autogenerated/src/ConditionCreator.cpp:719
#10 0x00007ffff7dea13a in call_init (l=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7fffffffcdb8, env=env@entry=0x7fffffffcdc8) at dl-init.c:78
#11 0x00007ffff7dea223 in call_init (env=<optimized out>, argv=<optimized out>, argc=<optimized out>, l=<optimized out>) at dl-init.c:36
#12 _dl_init (main_map=0x7ffff7ffe1c8, argc=1, argv=0x7fffffffcdb8, env=0x7fffffffcdc8) at dl-init.c:126
#13 0x00007ffff7ddb30a in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#14 0x0000000000000001 in ?? ()
#15 0x00007fffffffd1a7 in ?? ()
#16 0x0000000000000000 in ?? ()

This line gives it away:

#9  0x00007ffff6965013 in _GLOBAL__sub_I_ConditionCreator.cpp(void) () at /home/jbohren/ws/msl/src/cnc-msl/msl_expressions/autogenerated/src/ConditionCreator.cpp:719

The msl_expressions package was including the code that was initializing CGAL, but it was relying on CMAKE_CXX_FLAGS from one of the other packages. When built in isolation, it wasn't getting the flags it needed. This PR adds a cfg-extra which will automatically get all the CGAL stuff when someone depends on msl_worldmodel.

[StephanOpfer]

@jbohren Thank you, for your help. Now it is fixed.

We are still learning CMake and all that build dependency stuff. "catkin build" is a great tool, as it showed a lot of failures in our build configurations. To be honest, it took be 1 hour to remove all the failures, we had in our configurations. The astonishing fact is, that it all worked with "catkin_make" before.

The failure with the CGAL stuff, would have took be days to find! :)

I personally didn't know about the CFG_EXTRAS command, so here is the documentation for everyone interested: http://docs.ros.org/hydro/api/catkin/html/dev_guide/generated_cmake_api.html#catkin_package.