Description:
------------
2 warnings are generated when passed an unknown encoding, but one would suffice.The case sensitive versions only produce one.

Suggested code change in php_mb_stripos function

Move the following code to just below the "do {" line
		haystack.no_encoding = needle.no_encoding = mbfl_name2no_encoding(from_encoding);
		if (haystack.no_encoding == mbfl_no_encoding_invalid) {
			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Unknown encoding \"%s\"", from_encoding);
			break;
		}

Reproduce code:
---------------
<?php
var_dump(mb_strripos("abc abc abc", "b", 0, "invalid"));
var_dump(mb_stripos("abc abc abc", "b", 0, "invalid"));
?>

Expected result:
----------------
Warning: mb_strripos(): Unknown encoding "invalid" in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 2
bool(false)

Warning: mb_stripos(): Unknown encoding "invalid" in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 3
bool(false)


Actual result:
--------------
Warning: mb_strripos(): Illegal character encoding specified in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 2

Warning: mb_strripos(): Unknown encoding "invalid" in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 2
bool(false)

Warning: mb_stripos(): Illegal character encoding specified in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 3

Warning: mb_stripos(): Unknown encoding "invalid" in C:\udata-eclipse\p8\a.phpcode\testmb.php on line 3
bool(false)