openssl: The EVP GCM interface requires at least OpenSSL 1.0.1

src/libstrongswan/plugins/openssl/openssl_gcm.c

@@ -13,6 +13,10 @@
  * for more details.
  */
 
+#include <openssl/opensslv.h>
+
+#if OPENSSL_VERSION_NUMBER >= 0x1000100fL
+
 #include "openssl_gcm.h"
 
 #include <openssl/evp.h>
@@ -257,3 +261,5 @@ aead_t *openssl_gcm_create(encryption_algorithm_t algo, size_t key_size)
 
 	return &this->public;
 }
+
+#endif /* OPENSSL_VERSION_NUMBER */

src/libstrongswan/plugins/openssl/openssl_plugin.c

@@ -305,6 +305,7 @@ METHOD(plugin_t, get_features, int,
 			PLUGIN_PROVIDE(SIGNER, AUTH_HMAC_SHA2_512_256),
 #endif
 #endif /* OPENSSL_NO_HMAC */
+#if OPENSSL_VERSION_NUMBER >= 0x1000100fL
 #ifndef OPENSSL_NO_AES
 		/* AES GCM */
 		PLUGIN_REGISTER(AEAD, openssl_gcm_create),
@@ -318,6 +319,7 @@ METHOD(plugin_t, get_features, int,
 			PLUGIN_PROVIDE(AEAD, ENCR_AES_GCM_ICV16, 24),
 			PLUGIN_PROVIDE(AEAD, ENCR_AES_GCM_ICV16, 32),
 #endif /* OPENSSL_NO_AES */
+#endif /* OPENSSL_VERSION_NUMBER */
 #ifndef OPENSSL_NO_DH
 		/* MODP DH groups */
 		PLUGIN_REGISTER(DH, openssl_diffie_hellman_create),