awk: Use random(3) instead of rand(3)

While none of them is considered even near to cryptographic
level, random(3) is a better random generator than rand(3).

Use random(3) for awk as is done in other systems.

Thanks to Chenguang Li for discussing this in the lists
and submitting the patch upstream.

PR:		193147
MFC after:	5 weeks

contrib/one-true-awk/awk.1

@@ -208,7 +208,7 @@ or of
 if no argument.
 .TP
 .B rand
-random number on (0,1)
+random number on [0,1)
 .TP
 .B srand
 sets seed for

contrib/one-true-awk/main.c

@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
 	signal(SIGFPE, fpecatch);
 
 	srand_seed = 1;
-	srand(srand_seed);
+	srandom((unsigned long) srand_seed);
 
 	yyin = NULL;
 	symtab = makesymtab(NSYMTAB/NSYMTAB);

contrib/one-true-awk/run.c

@@ -1521,8 +1521,10 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 		u = (Awkfloat) system(getsval(x)) / 256;   /* 256 is unix-dep */
 		break;
 	case FRAND:
-		/* in principle, rand() returns something in 0..RAND_MAX */
+		/* random() returns numbers in [0..2^31-1]
-		u = (Awkfloat) (rand() % RAND_MAX) / RAND_MAX;
+		 * in order to get a number in [0, 1), divide it by 2^31
+		 */
+		u = (Awkfloat) random() / (0x7fffffffL + 0x1UL);
 		break;
 	case FSRAND:
 		if (isrec(x))	/* no argument provided */
@@ -1530,7 +1532,7 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 		else
 			u = getfval(x);
 		tmp = u;
-		srand((unsigned int) u);
+		srandom((unsigned long) u);
 		u = srand_seed;
 		srand_seed = tmp;
 		break;