Fix compilation when using Windows SDK <= 10.0.22000

Author: traversaro

.github/workflows/build.yml

@@ -94,13 +94,11 @@ jobs:
               -DMUJOCO_HARDEN:BOOL=ON
             tmpdir: "/tmp"
           - os: windows-2022
-            cmake_args: >-
-              -DCMAKE_SYSTEM_VERSION="10.0.22621.0"
+            cmake_args: ""
             cmake_build_args: "-- -m"
             tmpdir: "C:/Temp"
           - os: windows-2019
-            cmake_args: >-
-              -DCMAKE_SYSTEM_VERSION="10.0.22621.0"
+            cmake_args: ""
             cmake_build_args: "-- -m"
             tmpdir: "C:/Temp"
 

CMakeLists.txt

@@ -158,6 +158,13 @@ if(APPLE AND MUJOCO_BUILD_MACOS_FRAMEWORKS)
   )
 endif()
 
+# This code is a workaround for https://github.com/deepmind/mujoco/issues/862
+# Once it can be assumed that no users uses a Windows SDK < 10.0.22000
+# we can drop this code
+if(MSVC AND CMAKE_SYSTEM_VERSION VERSION_LESS 10.0.22000)
+  target_compile_definitions(mujoco PRIVATE MUJOCO_WINSDK_NO_STDALIGN_H)
+endif()
+
 # Add a namespace alias to mujoco to be used by the examples.
 # This simulates the install interface when building with sources.
 add_library(mujoco::mujoco ALIAS mujoco)

src/engine/engine_collision_driver.h

@@ -29,8 +29,12 @@ extern "C" {
 #error "Compiler does not support C11."
 #endif
 #else
+// This ifndef is workaround for https://github.com/deepmind/mujoco/issues/862
+// Remove once we can assume that no one uses WIN SDK < 10.0.22000
+#ifndef MUJOCO_WINSDK_NO_STDALIGN_H
 #include <stdalign.h>
 #endif
+#endif
 
 struct mjCollisionTree_ {
   alignas(mjtNum) int node1;