make pr ready for ros2cli security feature (ros2#1)

* update docs about possibility of rcl_take no taking (ros2#356)

* update rcl_wait doc with respect to subs and possibility of failing takes

* add a note about possible failing takes in rcl_take docs

* 0.6.2

* Set rmw_wait timeout using ros timers too (ros2#357)

* 0.6.3

* Avoid timer period being set to 0 (ros2#359)

* Fix logic that moves goal handles when one expires (ros2#360)

* Fix error from uncrustify v0.68 (ros2#364)

* Ensure that context instance id storage is aligned correctly (ros2#365)

* Ensure that context instance id storage is aligned correctly

* Make alignment compatible with MSVC

* Namespace alignment macro with RCL_

* [rcl] Guard against bad allocation calling rcl_arguments_copy() (ros2#367)

* [rcl] Add test for copying arguments struct with no arguments

* Override allocate function in test to reveal bug

* [rcl] Only allocate arrays if there are things to copy in rcl_argument_copy()

Also guard against freeing invalid pointers if rcl_argument_copy() fails.

* Remove uncessary guard against NULL pointer

* linter, styles, uncrustify fixes

rcl/include/rcl/security_directory.h

@@ -15,7 +15,13 @@
 #ifndef RCL__SECURITY_DIRECTORY_H_
 #define RCL__SECURITY_DIRECTORY_H_
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #include "rcl/allocator.h"
+#include "rcl/visibility_control.h"
 
 #ifndef ROS_SECURITY_NODE_DIRECTORY_VAR_NAME
   #define ROS_SECURITY_NODE_DIRECTORY_VAR_NAME "ROS_SECURITY_NODE_DIRECTORY"
@@ -29,11 +35,6 @@
   #define ROS_SECURITY_LOOKUP_TYPE_VAR_NAME "ROS_SECURITY_LOOKUP_TYPE"
 #endif
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 /// Return the secure root directory associated with a node given its validated name and namespace.
 /**
  * E.g. for a node named "c" in namespace "/a/b", the secure root path will be
@@ -50,10 +51,11 @@ extern "C"
  * \param[in] allocator the allocator to use for allocation
  * \returns machine specific (absolute) node secure root path or NULL on failure
  */
+RCL_PUBLIC
 const char * rcl_get_secure_root(
-    const char * node_name,
-    const char * node_namespace,
-    const rcl_allocator_t * allocator
+  const char * node_name,
+  const char * node_namespace,
+  const rcl_allocator_t * allocator
 );
 
 #ifdef __cplusplus