In pre-ANSI C compilers,
backslash/new-line pairs were allowed only as a means to continue
a directive, a string literal, or a character constant to the next line.
ANSI C extended the notion so that a backslash/new-line pair can
continue anything to the next line.
(The result is a
``logical source line.'')
Therefore, any code that relied on the separate recognition of
tokens on either side of a backslash/new-line pair will not behave as expected.