Patch from https://github.com/json-c/json-c/issues/173 to workaround sscanf

compatibility issue that causes test failures with Solaris libc.

Need to investigate if we should update our libc sscanf to be more compatible.

--- json-c-0.12/json_util.c.~1~ 2014-04-11 04:41:08.000000000 +0400

+++ json-c-0.12/json_util.c 2015-03-15 14:49:17.934357502 +0300

@@ -221,7 +222,7 @@

// Skip leading zeros, but keep at least one digit

while (buf_sig_digits[0] == '0' && buf_sig_digits[1] != '\0')

buf_sig_digits++;

- if (num64 == 0) // assume all sscanf impl's will parse -0 to 0

+ if (buf_sig_digits[0] == '0' && buf_sig_digits[1] == '\0')

orig_has_neg = 0; // "-0" is the same as just plain "0"

snprintf(buf_cmp_start, sizeof(buf_cmp), "%" PRId64, num64);