gcc: Escaped Newlines

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1 6.21 Slightly Looser Rules for Escaped Newlines
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1 The preprocessor treatment of escaped newlines is more relaxed than that
1 specified by the C90 standard, which requires the newline to immediately
1 follow a backslash.  GCC's implementation allows whitespace in the form
1 of spaces, horizontal and vertical tabs, and form feeds between the
1 backslash and the subsequent newline.  The preprocessor issues a
1 warning, but treats it as a valid escaped newline and combines the two
1 lines to form a single logical line.  This works within comments and
1 tokens, as well as between tokens.  Comments are _not_ treated as
1 whitespace for the purposes of this relaxation, since they have not yet
1 been replaced with spaces.
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