Re-add libvulkan.so.1 output name on linux

This helps reduce discrepancies with upstream.

Bug: 79706
Change-Id: Ia703596e84068d5ba9f64f5839c09d27c5968ea8
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/Vulkan-Loader/+/548445
Reviewed-by: Craig Stout <cstout@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 2753bf2..01f5a8d 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -188,6 +188,11 @@
       #configs += ["//build/config/fuchsia:static_cpp_standard_library"]
       libcxx_linkage = "static"
     }
+
+    # Create libvulkan.so.1 on Linux instead of libvulkan.so
+    if (is_linux && vulkan_loader_shared) {
+      output_extension = "so.1"
+    }
   }
 }
 
diff --git a/arg.gni b/arg.gni
index 99ec212..7a95554 100644
--- a/arg.gni
+++ b/arg.gni
@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-output_libvulkan_so_1 = false
+output_libvulkan_so_1 = true