openxpki: fix build

The openxpki build is not liking the multiple outputs of openssl. This
commit fixes the build, unfortunately not in the prettiest of ways.

pkgs/servers/openxpki/default.nix

@@ -50,7 +50,10 @@ buildPerlPackage {
       lib libapreq2 libnet podlators threads threadsshared version ];
 
   preConfigure = ''
-    export OPENSSL_PREFIX=${openssl}
+    substituteInPlace core/server/Makefile.PL \
+      --replace "my \$openssl_inc_dir = ''';" "my \$openssl_inc_dir = '${openssl}/include';" \
+      --replace "my \$openssl_lib_dir = ''';" "my \$openssl_lib_dir = '${openssl.out}/lib';" \
+      --replace "my \$openssl_binary  = ''';" "my \$openssl_binary  = '${openssl.bin}/bin/openssl';"
     substituteInPlace tools/vergen --replace "#!/usr/bin/perl" "#!${perl}/bin/perl"
     cp ${./vergen_revision_state} .vergen_revision_state
     cd core/server