[CMake] INCLUDE_DIR or INCLUDE_DIRS?

[Brad King]

Kedzierski, Artur CIV NAVSURFWARCENDIV CORONA wrote:
> 	I am looking at the readme.txt file in CMake's modules
> directory. It says:
> 
> Please use the following consistent variable names for general use.
> XXX_INCLUDE_DIRS  
> ...
> You do not have to provide all of the above variables. You should
> provide [...] XXX_INCLUDE_DIR [...]
> 
> 	Should I provide XXX_INCLUDE_DIR or XXX_INCLUDE_DIRS?

I've fixed the typo.  You should provide XXX_INCLUDE_DIRS, but note that
below that it says that there should not be a cache entry with this
name.  The cache entry (which the user might set) should be called
XXX_INCLUDE_DIR, but the final variable to be used by code should be
XXX_INCLUDE_DIRS.  The idea is there might be more than one include
directory, so the user would set XXX_YY_INCLUDE_DIR and
XXX_ZZ_INCLUDE_DIR and then the XXX_INCLUDE_DIRS variable would contain
both.

-Brad