Issue 43177

I changed main.c and Zend.c to address bug #43177.  The php.net description of eval() states:
"If there is a parse error in the evaluated code, eval() returns FALSE and execution of the following code continues normally."
That statement is almost true.  The exit status and http response code were made 255 and 500.  Even thought the script proceeds normally and the webpage may be perfectly constructed, the results may be discarded (e.g. by wget or an ajax framework) because of the 255/500.  The changes to main.c and Zend.c in this request prevent an eval() error from affecting the exit status and http response code.

This is my first attempt to submit a bug fix to php.  I believe I have followed the instructions at
https://wiki.php.net/vcs/gitworkflow
but I see that a half dozen files are listed as modified.  I guess that is a merge issue, but I don't see how I am supposed to address it.  I'm hoping it will be easy for whoever handles this pull request to only accept the relevant changes in main.c and zend.c.

Because the change regards the exit status and response code, testing does not appear to be compatible with the php test framework.  I have not added anything to the tests/ directory.