FindPythonLibs: Prefer libs early in search path regardless of name
Add NAMES_PER_DIR
to all find_library
invocations so that we
consider all possible names in each search directory before moving on to
the next directory. This helps find the package that appears earliest
in the search path regardless of how it names its libraries.
While at it, drop the NO_SYSTEM_ENVIRONMENT_PATH
option from our find_library
calls. No other find modules do this.
Fixes: #17336 (closed)