replace-regexp-lax-whitespace

replace-regexp-lax-whitespace is a variable defined in `replace.el'.
Its value is

nil

Documentation:
Non-nil means `query-replace-regexp' matches a sequence of whitespace chars.
When you enter a space or spaces in the regexps to be replaced,
it will match any sequence matched by the regexp `search-whitespace-regexp'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.