In the same spirit as the REQUIRED keyword on find_package, this will
stop cmake execution with an error on a failed find_program, find_file,
find_path or find_library.
Since commit v3.3.0-rc1~430^2 (Teach find_(library|file|path) to get
prefixes from PATH, 2015-02-18) we search in <prefix>/include and
<prefix>/lib directories for prefixes with bin directories in the PATH
environment variable. The motivation was to support MSYS, MinGW and
similar Windows platforms in their default environments automatically.
At the time this behavior was thought to be worthwhile in general.
Suggested-by: Chuck Atkins <chuck.atkins@kitware.com>
The find_package command already knows how to compute installation
prefixes from PATH. Use the same approach to establish prefixes for
find_library, find_file, and find_path to use to look in directories
like "<prefix>/lib[/<arch>]" and "<prefix>/include" for libraries and
headers. This will reduce the amount of configuration end users need to
do to establish a work environment rooted under a specific prefix.
