Merge topic 'dev/faster-evis' into next

41bdc474 Help: Add documentation on escaping changes with CMP0053
8d286927 Windows: Avoid () in environment variable references
ca46cb11 EVIS: Reimplement using custom parsing code
596bf9e6 EVIS: Add tests for syntax corner cases and CMP0053
c0c9a5ed EVIS: Add policy CMP0053
61b1b9b2 Utilities/Release: Use ${VAR} instead of @VAR@ syntax
27fbc318 Help: Add more reference targets to cmake-language.7
Help: Add more reference targets to cmake-language.7
Utilities/Release: Use ${VAR} instead of @VAR@ syntax

The Utilities/Release/Cygwin/CMakeLists.txt is processed in the project,
not configured, so we should avoid using @-replacement syntax.
EVIS: Add policy CMP0053

This policy switches between the old EVIS parser and the new, faster
parser.
EVIS: Add tests for syntax corner cases and CMP0053

Include tests for:

- @ expansion during normal execution
- various characters in variable names for comparison between the new
  and the old parser
- corner cases in the parsers
- correct messages when behavior is different
EVIS: Reimplement using custom parsing code

Testing the configure (no generate) step with ParaView shows ~20%
performance improvement.

In terms of complete configure/generate steps, further testing with
ParaView shows a 20% performance improvement over 2.8.12.2 with Unix
Makefiles and minimal with Ninja. Ninja is less because it generate step
is the expensive part (future work will address this) by a long shot and
these changes help the configure step for the most part.
Windows: Avoid () in environment variable references

Use nested variable evaluation instead.
Help: Add documentation on escaping changes with CMP0053
Help: Add release notes for policy CMP0053
Merge topic 'dev/faster-evis' into next

30d750fa Help: Add release notes for policy CMP0053