[CMake] Argh! Thwarted at every turn!

[Paul Smith]

On Fri, 2016-05-20 at 11:58 -0400, Paul Smith wrote:
> This is not nice but it does work...

Gah!  The last of my problems can be solved with add_dependencies().
Somehow I didn't see this and was looking through all the target
properties with set_properties() to find a way to add a dependency...
sigh.

Well, if anyone has a simpler way to solve the basic problem
(generating a link map which requires the .o files that will be used to
construct the shared library as input) I'm still interested.

So in makefile-ese I want to do something like this:

  mylib.so: $(OBJFILES) linkmap lib1 lib2 lib3
          $(CXX) ... -o $@ -Wl,--version-script=linkmap ...

  linkmap: $(OBJFILES)
          genlinkmap -o $@ $^