CMP0037
-------

Target names should match a validity pattern.

CMake 2.8.12 and lower allowed creating targets using :command:`add_library` and
:command:`add_executable` with unrestricted choice for the target name.  Newer
cmake features such as :manual:`cmake-generator-expressions(7)` and some
diagnostics expect target names to match a restricted pattern.

Target names may contain upper and lower case letters, numbers, the underscore
character (_), dot(.), plus(+) and minus(-).  As a special case, ALIAS
targets and INTERFACE library targets may contain two consequtive colons.

The OLD behavior for this policy is to allow creating targets which do not match
the validity pattern.  The NEW behavior for this policy is to report an error
if an add_* command is used with an invalid target name.

This policy was introduced in CMake version 3.0.0.  CMake version
|release| warns when the policy is not set and uses OLD behavior.  Use
the cmake_policy command to set it to OLD or NEW explicitly.
