Conditionally compile SSL and SASL

This allows building *.[ch] even when libssl and/or libsasl are not available.

This helps get the library to build for iOS, and similarly would be helpful for building the library under any third-party build system.

Sort of an aside: on Mac OS libssl is deprecated. iOS has never shipped with it. On Mac OS the headers are in /usr/include but aren't available when building an iOS project.

Ideally, someday, libmongoc would support both libssl and Common Crypto, Apple's implementation.

Author: paulmelnikow

src/mongoc/mongoc-b64-private.h

@@ -34,9 +34,11 @@ b64_ntop (uint8_t const *src,
 void
 b64_initialize_rmap (void);
 
+#ifdef MONGOC_ENABLE_SSL
 int
 b64_pton (char const *src,
           uint8_t    *target,
           size_t      targsize);
+#endif
 
 #endif /* MONGOC_B64_PRIVATE_H */

src/mongoc/mongoc-rand.c

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#ifdef MONGOC_ENABLE_SSL
+
 #include "mongoc-rand.h"
 #include "mongoc-rand-private.h"
 
@@ -40,3 +42,5 @@ void mongoc_rand_add(const void* buf, int num, double entropy) {
 int mongoc_rand_status(void) {
     return RAND_status();
 }
+
+#endif

src/mongoc/mongoc-sasl.c

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#ifdef MONGOC_ENABLE_SASL
 
 #include <string.h>
 
@@ -346,3 +347,5 @@ _mongoc_sasl_step (mongoc_sasl_t *sasl,
 
    return true;
 }
+
+#endif

src/mongoc/mongoc-scram.c

@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 
+#ifdef MONGOC_ENABLE_SSL
 
 #include <string.h>
 
@@ -799,3 +800,5 @@ _mongoc_scram_step (mongoc_scram_t *scram,
 
    return true;
 }
+
+#endif

src/mongoc/mongoc-ssl.c

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#ifdef MONGOC_ENABLE_SSL
 
 #include <bson.h>
 #include <limits.h>
@@ -548,3 +549,5 @@ _mongoc_ssl_thread_cleanup (void)
    }
    OPENSSL_free (gMongocSslThreadLocks);
 }
+
+#endif

src/mongoc/mongoc-stream-tls.c

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#ifdef MONGOC_ENABLE_SSL
 
 #include <bson.h>
 
@@ -799,3 +800,5 @@ mongoc_stream_tls_new (mongoc_stream_t  *base_stream,
 
    return (mongoc_stream_t *)tls;
 }
+
+#endif