[CMake] Generating multiple targets in parallel generates common prerequisites twice

[Martin Apel]

Hi all,

I hope this question hasn't been asked before, I haven't found anything 
useful in the archive.

Assume I have the following small CMakeLists.txt file:

CMAKE_MINIMUM_REQUIRED (VERSION 2.8)
PROJECT(testCMakeDeps)

ADD_LIBRARY(foo SHARED foo.cpp)
ADD_LIBRARY(bar SHARED bar.cpp)

ADD_EXECUTABLE(test test.cpp)
TARGET_LINK_LIBRARIES(test foo bar)

ADD_EXECUTABLE(test2 test2.cpp)
TARGET_LINK_LIBRARIES(test2 foo bar)

This creates two executables, which both depend on the same two shared 
libraries. When generating a Makefile for this on Linux,
one can start the compilation process via 'make -j2 test test2', i.e. 
name two separate targets on the command line.
However CMake seems to generate a Makefile, which does not work 
correctly in this case. The shared libraries are generated twice.
This seems to be a CMake issue, not a Make issue, I can write a Makefile 
by hand, which works correctly in this case.
Is there any way around the duplicate generation (which sometimes fails, 
because the same libraries may be generated simultaneously)?

Martin