printf.3: Formatting fixes in example code

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man3/printf.3

@@ -1035,8 +1035,8 @@ To allocate a sufficiently large string and print into it
 char *
 make_message(const char *fmt, ...)
 {
-    /* Guess we need no more than 100 bytes. */
-    int n, size = 100;
+    int n;
+    int size = 100;     /* Guess we need no more than 100 bytes. */
     char *p, *np;
     va_list ap;
 
@@ -1044,18 +1044,25 @@ make_message(const char *fmt, ...)
         return NULL;
 
     while (1) {
+
         /* Try to print in the allocated space. */
+
         va_start(ap, fmt);
         n = vsnprintf(p, size, fmt, ap);
         va_end(ap);
+
         /* If that worked, return the string. */
+
         if (n > \-1 && n < size)
             return p;
+
         /* Else try again with more space. */
+
         if (n > \-1)    /* glibc 2.1 */
             size = n+1; /* precisely what is needed */
         else           /* glibc 2.0 */
             size *= 2;  /* twice the old size */
+
         if ((np = realloc (p, size)) == NULL) {
             free(p);
             return NULL;