address win32 build issues

- Replace external -DOPENSSL/-DPKCS11CRYPTO with properly AC_DEFINEd
  HAVE_OPENSSL/HAVE_PKCS11
- Don't enforce the crypto provider from platform.h, just from dst_api.c
  and configure scripts

lib/dns/tests/sigs_test.c

@@ -17,7 +17,6 @@
 
 #include <isc/util.h>
 
-#if defined(OPENSSL) || defined(PKCS11CRYPTO)
 #include <string.h>
 
 #include <dns/db.h>
@@ -457,23 +456,9 @@ ATF_TC_BODY(updatesigs, tc) {
 
 	dns_test_end();
 }
-#else
-ATF_TC(untested);
-ATF_TC_HEAD(untested, tc) {
-        atf_tc_set_md_var(tc, "descr", "skipping dns__zone_updatesigs() test");
-}
-ATF_TC_BODY(untested, tc) {
-        UNUSED(tc);
-        atf_tc_skip("DNSSEC support not compiled in");
-}
-#endif
 
 ATF_TP_ADD_TCS(tp) {
-#if defined(OPENSSL) || defined(PKCS11CRYPTO)
 	ATF_TP_ADD_TC(tp, updatesigs);
-#else
-	ATF_TP_ADD_TC(tp, untested);
-#endif
 
 	return (atf_no_error());
 }