Description:
------------
The attached patch adds support to alternatively open a try block using a colon (:) in try/catch structures. When using this syntax, each catch block must also be open by a colon, try and catch blocks must not be closed by a closing brace (}), and the whole try/catch structure must be closed by a "endtry" keyword.

The idea is to provide greater readability when PHP code is intermixed with HTML code and keep consistency with constructs like if/endif, for/foreach, etc...

Please, note that after patching, the Zend scanner and parser, as well as ext/tokenizer_data.c should be regenerated (using re2c, bison and tokenizer_data_gen.sh respectively, or using the provided Makefile targets).



Test script:
---------------
<?php
try:
	echo "Trying something unsafe\n";
	throw new Exception('thrown using alternative try/catch syntax');
catch (int $e):
	echo "Caught exception of type int (ints are not throwable, this is just example)\n";
	// several statements can also be used here
catch (Exception $e):
	echo "Caught exception of type Exception: {$e->getMessage()}\n";
	// several statements can also be used here
endtry;
?>
<?php try:?>
<p>Trying something unsafe</p>
<?php throw new Exception('thrown using alternative try/catch syntax');?>
<?php catch (int $e):?>
<p>Caught exception of type int (ints are not throwable, this is just example)</p>
<?php catch (Exception $e):?>
<p>Caught exception of type Exception: <?php echo $e->getMessage();?></p>
<?php endtry;?>

Expected result:
----------------
Trying something unsafe
Caught exception of type Exception: thrown using alternative try/catch syntax
<p>Trying something unsafe</p>
<p>Caught exception of type Exception: thrown using alternative try/catch syntax</p>

Actual result:
--------------
PHP Parse error:  syntax error, unexpected ':', expecting '{' in /home/aaa/test.php on line 2

Parse error: syntax error, unexpected ':', expecting '{' in /home/aaa/test.php on line 2