Warning: skipping dependency checks. hdr_histogram.c: In function ‘hdr_reset_internal_counters’: hdr_histogram.c:211:5: error: ‘for’ loop initial declarations are only allowed in C99 mode for (int i = 0; i < h->counts_len; i++) ^ hdr_histogram.c:211:5: note: use option -std=c99 or -std=gnu99 to compile your code hdr_histogram.c: In function ‘shift_lowest_half_bucket_contents_left’: hdr_histogram.c:385:5: error: ‘for’ loop initial declarations are only allowed in C99 mode for (int from_index = 1; from_index < h->sub_bucket_half_count; from_index++) ^ Error: Build error: Failed compiling object hdr_histogram.o