void crlf_to_lf(char* dst, char* src, size_t n)
{
int was_cr = 0;
for (size_t i=0; i<n; i++)
{
char c = src[i];
if (was_cr && c=='\n') dst--;
dst[i] = c;
was_cr = (c=='\r');
}
}
CR LF ← ⎕UCS 13 10
crlf_to_lf ← {((CR≠⍵) ∨ 1⌽LF≠⍵) / ⍵}