vulkan: add symbols file

According to the Vulkan ICD spec [1], these two symbols must be exposed:
- vk_icdGetInstanceProcAddr
- vk_icdNegotiateLoaderICDInterfaceVersion

and this one is optional:
- vk_icdGetPhysicalDeviceProcAddr

[1] https://github.com/KhronosGroup/Vulkan-Loader/blob/master/loader/LoaderAndLayerInterface.md

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/vulkan/meson.build

@@ -19,6 +19,7 @@
 # SOFTWARE.
 
 vk_api_xml = files('registry/vk.xml')
+vulkan_icd_symbols = files('vulkan-icd-symbols.txt')
 
 inc_vulkan_wsi = include_directories('wsi')
 

src/vulkan/vulkan-icd-symbols.txt

@@ -0,0 +1,14 @@
+# See loader/LoaderAndLayerInterface.md in
+# https://github.com/KhronosGroup/Vulkan-Loader
+# and vulkan/vk_icd.h
+
+# Version 1 - Add support for vk_icdGetInstanceProcAddr.
+vk_icdGetInstanceProcAddr
+
+# Version 2 - Add Loader/ICD Interface version negotiation
+#             via vk_icdNegotiateLoaderICDInterfaceVersion.
+vk_icdNegotiateLoaderICDInterfaceVersion
+
+# Version 4 - Add unknown physical device extension querying via
+#             vk_icdGetPhysicalDeviceProcAddr.
+(optional) vk_icdGetPhysicalDeviceProcAddr