openssl: only include necessary headers

Avoid #include'ing the openssl_dynamic.h headers, which allows a user to
exclude them from their source tree, in case they have odd license
requirements.

src/libgit2/streams/openssl.c

@@ -6,8 +6,6 @@
  */
 
 #include "streams/openssl.h"
-#include "streams/openssl_legacy.h"
-#include "streams/openssl_dynamic.h"
 
 #ifdef GIT_OPENSSL
 

src/libgit2/streams/openssl.h

@@ -8,8 +8,14 @@
 #define INCLUDE_streams_openssl_h__
 
 #include "common.h"
-#include "streams/openssl_legacy.h"
-#include "streams/openssl_dynamic.h"
+
+#if defined(GIT_OPENSSL_LEGACY)
+# include "streams/openssl_legacy.h"
+#endif
+
+#if defined(GIT_OPENSSL_DYNAMIC)
+# include "streams/openssl_dynamic.h"
+#endif
 
 #include "git2/sys/stream.h"
 

src/libgit2/streams/openssl_legacy.h

@@ -7,7 +7,9 @@
 #ifndef INCLUDE_streams_openssl_legacy_h__
 #define INCLUDE_streams_openssl_legacy_h__
 
-#include "streams/openssl_dynamic.h"
+#ifdef GIT_OPENSSL_DYNAMIC
+# include "streams/openssl_dynamic.h"
+#endif
 
 #if defined(GIT_OPENSSL) && !defined(GIT_OPENSSL_DYNAMIC)
 # include <openssl/ssl.h>