[CMake] Obtaining improved GNU make performance on Makefiles generated by cmake

[Alan W. Irwin]

On 2008-03-24 10:27-0400 Bill Hoffman wrote:

> One more warning about adding your own -I flags...  I think this will break 
> the dependency scanner of CMake, and the depends will be wrong if you do not 
> use include_directories.

Our use case is we have a directory where our many different device drivers
are built with wildly varying compilation flag (both -I and -D)
requirements.  So it seemed natural to use SET_SOURCE_FILES_PROPERTIES( ...
PROPERTIES COMPILE_FLAGS ...) to handle each device driver separately rather
than using ADD_DEFINITIONS and INCLUDE_DIRECTORIES.  The method appears to
work fine, but I haven't tested the case where some external library header
has been changed to see if CMake responds properly.  I will probably just
stick with the present method until CMake adds the feature of per-target
ADD_DEFINITIONS and INCLUDE_DIRECTORIES (assuming they do handle the
external dependency case correctly).

For PLplot headers scattered all over our build tree for our various
libraries we do use INCLUDE_DIRECTORIES to find them so all the internal
dependencies should be correct.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
__________________________

Linux-powered Science
__________________________