Assignment within condition expression warning

[pete@…]

In many places in my own code I get the following warning from Microsoft compilers:

<boost\spirit\home\qi\detail\string_parse.hpp> line 22 : warning C4706: assignment within conditional expression

Of course on this occasion the assignment is safe and intended. However it is not a warning that we feel comfortable disabling globally. Hence it would be nice if the warning could be push'n'pop-ed inside Boost code to save client workarounds.

An alernative - moving the assignment inside the loop - has the potential for a slight performance loss - an extra iterator deference.

[Hartmut Kaiser]

(In [53540]) Spirit: refactored loop to avoid warning about assignment in conditional expression (fix #2902)