/* Determine the grapheme cluster boundaries in S, and store the result at
p[0..n-1]. p[i] = 1 means that a new grapheme cluster begins at s[i]. p[i]
/* Determine the grapheme cluster boundaries in S, and store the result at
p[0..n-1]. p[i] = 1 means that a new grapheme cluster begins at s[i]. p[i]