http://www.berklix.com/~jhs/src/bsd/fixes/FreeBSD/src/gen/usr.bin/fmt/fmt.c.call.REL=10.3-RELEASE.diff

*** 10.3-p11/src/usr.bin/fmt/fmt.c	Thu Sep 28 14:10:52 2017
--- new/src/usr.bin/fmt/fmt.c	Thu Sep 28 14:15:13 2017
***************
*** 700,706 ****
    while ((ch=getwc(stream)) != '\n' && ch != WEOF) {
      if (len+spaces_pending==0 && ch=='.' && !format_troff) troff=1;
      if (ch==' ') ++spaces_pending;
!     else if (troff || iswprint(ch)) {
        while (len+spaces_pending >= length) {
          length*=2; buf=xrealloc(buf, length * sizeof(wchar_t));
        }
--- 700,706 ----
    while ((ch=getwc(stream)) != '\n' && ch != WEOF) {
      if (len+spaces_pending==0 && ch=='.' && !format_troff) troff=1;
      if (ch==' ') ++spaces_pending;
!     else if (troff || iswprintext(ch)) {
        while (len+spaces_pending >= length) {
          length*=2; buf=xrealloc(buf, length * sizeof(wchar_t));
        }