forward declare aws_string to fix C++ builds. (#222)

* forward declare aws_string to fix C++ builds.

Author: JonathanHenson

CMakeLists.txt

@@ -32,6 +32,7 @@ include(AwsCheckHeaders)
 include(AwsSharedLibSetup)
 include(AwsSanitizers)
 include(AwsFindPackage)
+include(CTest)
 
 option(BUILD_RELOCATABLE_BINARIES
         "Build Relocatable Binaries, this will turn off features that will fail on older kernels than used for the build."
@@ -219,7 +220,10 @@ install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-config.cmake"
         DESTINATION "${LIBRARY_DIRECTORY}/${PROJECT_NAME}/cmake/"
         COMPONENT Development)
 
-include(CTest)
-if (BUILD_TESTING)
-    add_subdirectory(tests)
-endif ()
+if (NOT CMAKE_CROSSCOMPILING)
+    if (BUILD_TESTING)
+       add_subdirectory(tests)
+    endif()
+endif()
+
+

include/aws/io/tls_channel_handler.h

@@ -15,12 +15,12 @@
  * permissions and limitations under the License.
  */
 #include <aws/common/byte_buf.h>
-#include <aws/common/string.h>
 
 #include <aws/io/io.h>
 
 struct aws_channel_slot;
 struct aws_channel_handler;
+struct aws_string;
 
 enum aws_tls_versions {
     AWS_IO_SSLv3,

source/darwin/secure_transport_tls_channel_handler.c

@@ -21,6 +21,7 @@
 #include <aws/io/logging.h>
 
 #include <aws/common/encoding.h>
+#include <aws/common/string.h>
 #include <aws/common/task_scheduler.h>
 
 #include <AvailabilityMacros.h>

source/s2n/s2n_tls_channel_handler.c

@@ -20,6 +20,7 @@
 #include <aws/io/logging.h>
 #include <aws/io/pki_utils.h>
 
+#include <aws/common/string.h>
 #include <aws/common/task_scheduler.h>
 #include <aws/common/thread.h>
 

source/tls_channel_handler.c

@@ -18,6 +18,8 @@
 #include <aws/io/logging.h>
 #include <aws/io/tls_channel_handler.h>
 
+#include <aws/common/string.h>
+
 void aws_tls_ctx_options_init_default_client(struct aws_tls_ctx_options *options, struct aws_allocator *allocator) {
     AWS_ZERO_STRUCT(*options);
     options->allocator = allocator;

source/windows/secure_channel_tls_handler.c

@@ -17,6 +17,7 @@
 #include <aws/io/tls_channel_handler.h>
 
 #include <aws/common/math.h>
+#include <aws/common/string.h>
 #include <aws/common/task_scheduler.h>
 
 #include <aws/io/channel.h>