Description:
------------
When mbstring.encoding_translation is set to on, and passing a variable like x=%FC (ISO '?' character) the mb lib is hanging in itself.

Following settings are applyied (internal encoding is ISO):

Multibyte Support 	enabled
Multibyte string engine 	libmbfl
HTTP input encoding translation 	enabled
Multibyte (japanese) regex support 	enabled
Multibyte regex (oniguruma) version 	4.4.4
Multibyte regex (oniguruma) backtrack check 	On

mbstring extension makes use of "streamable kanji code filter and converter", which is distributed under the GNU Lesser General Public License version 2.1.

Directive	Local Value	Master Value
mbstring.detect_order	auto	no value
mbstring.encoding_translation	On	Off
mbstring.func_overload	0	0
mbstring.http_input	UTF-8,ISO-8859-15	pass
mbstring.http_output	ISO-8859-15	pass
mbstring.internal_encoding	ISO-8859-15	no value
mbstring.language	neutral	neutral
mbstring.strict_detection	On	Off
mbstring.substitute_character	no value	no value


Also not working with these settings (internal UTF8)
mbstring.detect_order	auto	auto
mbstring.encoding_translation	On	On
mbstring.func_overload	0	7
mbstring.http_input	UTF-8,ISO-8859-15	auto
mbstring.http_output	UTF-8	UTF-8
mbstring.internal_encoding	UTF-8	UTF-8
mbstring.language	neutral	neutral
mbstring.strict_detection	On	Off
mbstring.substitute_character	no value	no value

Reproduce code:
---------------
Pass a ?x=%FC as a parameter. When followed by other parameters, it is working again.

Expected result:
----------------
No hang.

Actual result:
--------------
Hang (99.9% CPU usage). As a result the script will be aborted later on with "Max execution time exceeded". The first line of PHP Code itself is never called.

GDB Info:
(gdb) where
#0  0xb752e9d5 in mbfl_encoding_detector_judge () from /usr/lib/apache2/modules/libphp5.so
#1  0xb753c93e in _php_mb_encoding_handler_ex () from /usr/lib/apache2/modules/libphp5.so
#2  0xbffd34ec in ?? ()