Fix determination of Perl interpreter: A perl or perl5

_directory_ in $PATH was also accepted as the interpreter.

CHANGES

@@ -2,9 +2,12 @@
  OpenSSL CHANGES
  _______________
 
-
  Changes between 0.9.3a and 0.9.4
 
+  *) Fix determination of Perl interpreter: A perl or perl5
+     _directory_ in $PATH was also accepted as the interpreter.
+     [Ralf S. Engelschall]
+
   *) Fix demos/sign/sign.c: well there wasn't anything strictly speaking
      wrong with it but it was very old and did things like calling
      PEM_ASN1_read() directly and used MD5 for the hash not to mention some

Configure

@@ -753,7 +753,7 @@ sub which
 	my $path;
 	foreach $path (split /:/, $ENV{PATH})
 		{
-		if (-x "$path/$name")
+		if (-f "$path/$name" and -x _)
 			{
 			return "$path/$name" unless ($name eq "perl" and
 			 system("$path/$name -e " . '\'exit($]<5.0);\''));