Extend workaround for TCP fragmentation

Instead of checking via uname for Linux this commit does a check
whether the outcome for an external printf is what is expected. This
makes it more compatible e.g. with OpenBSD which surprisingly works
similar like the GNU counterpart.

Also it checks all external printfs installed wther it's the
"right one" to use. Previously it stopped just at the first one
and if this was "wrong", bash's printf was used.

testssl.sh

@@ -267,6 +267,7 @@ declare -r UA_SNEAKY="Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Fi
 
 ########### Initialization part, further global vars just being declared here
 #
+PRINTF=""                               # which external printf to use
 IKNOW_FNAME=false
 FIRST_FINDING=true                      # is this the first finding we are outputting to file?
 JSONHEADER=true                         # include JSON headers and footers in HTML file, if one is being created
@@ -1114,7 +1115,6 @@ debugme() {
 }
 
 hex2dec() {
-     #/usr/bin/printf -- "%d" 0x"$1"
      echo $((16#$1))
 }
 
@@ -15440,13 +15440,21 @@ check_bsd_mount() {
 # This sets the PRINTF command for writing into TCP sockets. It is needed because
 # The shell builtin printf flushes the write buffer at every \n, ("\x0a") which
 # in turn means a new TCP fragment. That causes a slight performance penalty and
-# and some F5s to hiccup, see #1113. Unfortunately this can be only used under 
-# Linux, see #1134. A better solution needs to follow
+# and some F5s to hiccup, see #1113. Unfortunately this can be used only with GNU's
+# and OpenBSD's /usr/bin/printf -- FreeBSD + OS X can't do this.
+# A better solution needs to follow.
 #
 choose_printf() {
-     PRINTF="$(type -P printf)"
-     if [[ -n "$PRINTF" ]] && [[ "$SYSTEM" == Linux ]]; then
-           return 0
+     local p ptf
+
+     ptf="$(type -aP printf)"
+     if [[ -n "$ptf" ]]; then
+          for p in $ptf; do
+               if $p "\xc0\x14\xc0\xff\xee" | hexdump -C  | grep -q 'c0 14 c0 ff ee'; then
+                    PRINTF=$p
+                    return 0
+               fi
+          done
      fi
      if type -t printf >/dev/null; then
           PRINTF=printf
@@ -15610,7 +15618,7 @@ os constraint: $SYSTEM2
 shellopts: $SHELLOPTS
 printf: $PRINTF
 
-$($OPENSSL version -a)
+$($OPENSSL version -a 2>/dev/null)
 OSSL_VER_MAJOR: $OSSL_VER_MAJOR
 OSSL_VER_MINOR: $OSSL_VER_MINOR
 OSSL_VER_APPENDIX: $OSSL_VER_APPENDIX
@@ -17860,13 +17868,13 @@ lets_roll() {
      set_color_functions
      maketempf
      find_openssl_binary
+     choose_printf
      prepare_debug  ; stopwatch parse
      prepare_arrays ; stopwatch prepare_arrays
      mybanner
      check_proxy
      check4openssl_oldfarts
      check_bsd_mount
-     choose_printf
 
      if "$do_display_only"; then
           prettyprint_local "$PATTERN2SHOW"