Give hint on what version of OpenSSL is required

build/autotools/includes/acinclude.m4

@@ -592,7 +592,7 @@ AC_TRY_COMPILE([#include <openssl/opensslv.h>],[
 [AC_MSG_RESULT(OK)],
 [
   AC_MSG_RESULT([too old.])
-  AC_MSG_ERROR([OpenSSL version is too old.], 1)
+  AC_MSG_ERROR([OpenSSL version is too old. Must be 0.9.8f+], 1)
 ]
 )
 

configure

@@ -5541,7 +5541,7 @@ else
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: too old." >&5
 $as_echo "too old." >&6; }
-  as_fn_error 1 "OpenSSL version is too old." "$LINENO" 5
+  as_fn_error 1 "OpenSSL version is too old. Must be 0.9.8f+" "$LINENO" 5
 
 
 fi