Description:
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Echo sometimes strips double-quotes from tags.

It seems impossible to echo the following string literal:

 <a " >

Tested on localhost with:

 PHP 4.3.11-dev as CGI with Apache 1.3.33 on Windows 98
 PHP 4.3.10 as CGI with Apache 1.3.33 on Windows 98

Tested remotely with:

 PHP 4.3.10 as CGI with Apache 1.3.33 on Linux kernal 2.4.28

Reproduce code:
---------------
# Echo strips double-quotes from these strings... (unexpected behaviour)

echo '<a " >';
echo "<a \" >";


# But does not strip double-quotes from these strings... (exepected behaviour)

echo '< " >';
echo "< \" >";

echo '<a a="" >';
echo "<a a=\"\" >";


# Character references are output as character references, not as literal characters... (expected behaviour)

echo '< &quot; >';
echo '< &#34; >';

Expected result:
----------------
<a " ><a " >< " >< " ><a a="" ><a a="" >< &quot; >< &#34; >

Actual result:
--------------
<a  ><a  >< " >< " ><a a="" ><a a="" >< &quot; >< &#34; >