Bug 31404

Description of problem:

regcomp() should correctly find the occurences of '{ ' in a string, since it is said: (man 7 regex) 
A  '{'  followed by a character other than a digit is an ordinary character, not the beginning of a bound(!).

Version-Release number of selected component (if applicable):


How reproducible:
Always.

Steps to Reproduce:
1. compile and run this small C code below (slightly edited copy of the man example). 
2. the result is OK on, e.g., OSX. Not on Mageia 8, an error is issued. Instead it should find the positions of '{ ' in the string "1234 G!t!rk{ ss { zz...\n" 
3. the code:
      #include <stdint.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <regex.h>

       #define ARRAY_SIZE(arr) (sizeof((arr)) / sizeof((arr)[0]))

       static const char *const str =  "1234 G!t!rk{ ss { zz...\n";
       static const char *const re = "{ ";

       int main(void)
       {
           static const char *s = str;
           regex_t     regex;
           regmatch_t  pmatch[1];
           regoff_t    off, len;
int cflags = REG_EXTENDED;
 int res=regcomp(&regex, re, cflags);
 if (res) {
   printf("regcomp error:");
   if (res == REG_BADBR   ) printf(" REG_BADBR   ");
   if (res == REG_BADPAT  ) printf(" REG_BADPAT  ");
   if (res == REG_BADRPT  ) printf(" REG_BADRPT  ");
   if (res == REG_EBRACE  ) printf(" REG_EBRACE  ");
   if (res == REG_EBRACK  ) printf(" REG_EBRACK  ");
   if (res == REG_ECOLLATE) printf(" REG_ECOLLATE");
   if (res == REG_ECTYPE  ) printf(" REG_ECTYPE  ");
   /* if (res == REG_EEND    ) printf(" REG_EEND    "); */
   if (res == REG_EESCAPE  ) printf(" REG_EESCAPE  ");
   if (res == REG_EPAREN  ) printf(" REG_EPAREN  ");
   if (res == REG_ERANGE  ) printf(" REG_ERANGE  ");
   /* if (res == REG_ESIZE   ) printf(" REG_ESIZE   ");  */
   if (res == REG_ESPACE  ) printf(" REG_ESPACE  ");
   if (res == REG_ESUBREG ) printf(" REG_ESUBREG ");
   printf("\n");
  exit(EXIT_FAILURE);
 }

           printf("String = \"%s\"\n", str);
           printf("Matches:\n");

           for (int i = 0; ; i++) {
               if (regexec(&regex, s, ARRAY_SIZE(pmatch), pmatch, 0))
                   break;

               off = pmatch[0].rm_so + (s - str);
               len = pmatch[0].rm_eo - pmatch[0].rm_so;
               printf("#%d:\n", i);
               printf("offset = %jd; length = %jd\n", (intmax_t) off,
                       (intmax_t) len);
               printf("substring = \"%.*s\"\n", len, s + pmatch[0].rm_so);

               s += pmatch[0].rm_eo;
           }

           exit(EXIT_SUCCESS);
       }