Add Lua-style long brackets and long comments to CMake language

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.

1 files changed, 6 insertions, 0 deletions

diff --git a/Tests/RunCMake/Syntax/BracketBackslash-stderr.txt b/Tests/RunCMake/Syntax/BracketBackslash-stderr.txt
new file mode 100644
index 0000000..b746953
--- /dev/null
+++ b/Tests/RunCMake/Syntax/BracketBackslash-stderr.txt
@@ -0,0 +1,6 @@
+CMake Error at BracketBackslash.cmake:1 \(message\):
+  a\\
+
+  b
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$