Revert "Remove tests that depend on TLS or X.509"

This reverts commit 9afb2e992136db3fae9a669c3faaf6d5d27602a8.

Conflicts:
* include/CMakeLists.txt
  * "Make config.h available" comment: there has been a change
    adjacent to where it was removed. Just re-add what was removed.
* tests/CMakeLists.txt:
  * compat.sh: there has been a change immediately before where it was
    removed. Just re-add what was removed.
diff --git a/tests/Descriptions.txt b/tests/Descriptions.txt
index 3e9b255..8b13bb3 100644
--- a/tests/Descriptions.txt
+++ b/tests/Descriptions.txt
@@ -2,9 +2,21 @@
     The various 'test_suite_XXX' programs from the 'tests' directory, executed
     using 'make check' (Unix make) or 'make test' (Cmake), include test cases
     (reference test vectors, sanity checks, malformed input for parsing
-    functions, etc.) for all modules.
+    functions, etc.) for all modules except the SSL modules.
 
 selftests
     The 'programs/test/selftest' program runs the 'XXX_self_test()' functions
     of each individual module. Most of them are included in the respective
     test suite, but some slower ones are only included here.
+
+compat
+    The 'tests/compat.sh' script checks interoperability with OpenSSL and
+    GnuTLS (and ourselves!) for every common ciphersuite, in every TLS
+    version, both ways (client/server), using client authentication or not.
+    For each ciphersuite/version/side/authmode it performs a full handshake
+    and a small data exchange.
+
+ssl_opt
+    The 'tests/ssl-opt.sh' script checks various options and/or operations not
+    covered by compat.sh: session resumption (using session cache or tickets),
+    renegotiation, SNI, other extensions, etc.