find_library: Infer library prefix and suffix when in script mode
This aligns find_library
with the documentation that states it
can be called from script mode. This is done by infering the
proper prefix and suffix values when find_library
is called
when the CMAKE_FIND_LIBRARY*
are not set. This also means that
find_library
won't produce obscure error messages about unset
definitions.
Fixes: #22027 (closed)
Edited by Robert Maynard