Teach the CMake language parser to recognize Lua-style "long bracket"
arguments. These start with two '[' separated by zero or more '='
characters e.g. "[[" or "[=[" or "[==[". They end with two ']'
separated by the same number of '=' as the opening bracket. There is no
nesting of brackets of the same level (number of '='). No escapes,
variable expansion, or other processing is performed on the content
between such brackets so they always represent exactly one argument.
Also teach CMake to parse and ignore "long comment" syntax. A long
comment starts with "#" immediately followed by an opening long bracket.
It ends at the matching close long bracket.
Teach the RunCMake.Syntax test to cover long bracket and long comment
cases.
Teach the lexer to read a UTF-8, UTF-16 BE/LE, or UTF-32 BE/LE
Byte-Order-Mark from the start of a file if any is present. Report an
error on files using UTF-16 or UTF-32 and accept a UTF-8 or missing BOM.
Teach the lexer to return tokens for whitespace. Teach the parser to
tolerate the space tokens where whitespace is allowed. Also teach the
parser to diagnose and warn about cases of quoted arguments followed
immediately by another argument. This was accidentally allowed
previously, so we only warn.
Update the RunCMake.Syntax test case StringNoSpace expected stderr to
include the warnings.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.
