gl_add_char_to_line
if(gl_end_of_line(gl, 1, NULL) || gl_add_char_to_line(gl, newline_char))
gl_add_char_to_line(gl, c);
gl_add_char_to_line(gl, c);
if(gl_add_char_to_line(gl, gl->vi.undo.line[i]))
gl_add_char_to_line(gl, first_char);
static int gl_add_char_to_line(GetLine *gl, char c);