RE_NEWLINE_ALT
# define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
| RE_NEWLINE_ALT)
| RE_NEWLINE_ALT | RE_NO_BK_PARENS \
if (syntax & RE_NEWLINE_ALT)
#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
| RE_NEWLINE_ALT)
| RE_NEWLINE_ALT | RE_NO_BK_PARENS \
if (syntax & RE_NEWLINE_ALT)
if (!(syntax & RE_NEWLINE_ALT) || prev != '\n')