Clarify Vulkan compilation and extension/version requirements in Remo…

…tery.h and README

lib/Remotery.h

@@ -31,7 +31,10 @@ Compiling
   -I lib -pthread -lm
 
 * Vulkan - Ensure your include directories are set such that the Vulkan headers can be
-  included with the statement: #include <vulkan/vulkan.h>.
+  included with the statement: #include <vulkan/vulkan.h>. Currently the Vulkan implementation
+  requires either Vulkan 1.2+ with the "hostQueryReset" and "timelineSemaphore" features enabled,
+  or < 1.1 with the "VK_EXT_host_query_reset" and "VK_KHR_timeline_semaphore" extensions. The
+  extension "VK_EXT_calibrated_timestamps" is also always required.
 
 You can define some extra macros to modify what features are compiled into Remotery. These are
 documented just below this comment.

readme.md

@@ -47,6 +47,12 @@ Compiling
   ([devel/remotery](https://www.freshports.org/devel/remotery/)) and modify the port's
   Makefile if needed. There is also a package available via `pkg install remotery`.
 
+* Vulkan - Ensure your include directories are set such that the Vulkan headers can be
+  included with the statement: `#include <vulkan/vulkan.h>`. Currently the Vulkan implementation
+  requires either Vulkan 1.2+ with the `hostQueryReset` and `timelineSemaphore` features enabled,
+  or < 1.1 with the `VK_EXT_host_query_reset` and `VK_KHR_timeline_semaphore` extensions. The
+  extension `VK_EXT_calibrated_timestamps` is also always required.
+
 You can define some extra macros to modify what features are compiled into Remotery:
 
     Macro               Default     Description