Define ADDRESS_SANITIZER portably using standard compiler macros

Use `__SANITIZE_ADDRESS__` (GCC) and `__has_feature(address_sanitizer)` (Clang)
to define ADDRESS_SANITIZER when the toolchain doesn't provide it natively.

Fixes #3160

PiperOrigin-RevId: 884447485
Change-Id: I48ef51bca8f5c5f15f62089e73cd8fa649723636

include/mujoco/mjsan.h

@@ -15,6 +15,13 @@
 #ifndef MUJOCO_INCLUDE_MJSAN_H_
 #define MUJOCO_INCLUDE_MJSAN_H_
 
+// Define ADDRESS_SANITIZER if implied by other macros.
+#if !defined(ADDRESS_SANITIZER)
+  #if defined(__SANITIZE_ADDRESS__) || (defined(__has_feature) && __has_feature(address_sanitizer))
+    #define ADDRESS_SANITIZER
+  #endif
+#endif
+
 // Include asan interface header, or provide stubs for poison/unpoison macros when not using asan.
 #ifdef ADDRESS_SANITIZER
   #include <sanitizer/asan_interface.h>

src/engine/engine_crossplatform.h

@@ -58,6 +58,13 @@
   #define mjUNLIKELY(x) (x)
 #endif
 
+// Define ADDRESS_SANITIZER if implied by other macros.
+#if !defined(ADDRESS_SANITIZER)
+  #if defined(__SANITIZE_ADDRESS__) || (defined(__has_feature) && __has_feature(address_sanitizer))
+    #define ADDRESS_SANITIZER
+  #endif
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif

src/engine/engine_memory.h

@@ -17,6 +17,8 @@
 
 #include <mujoco/mjdata.h>
 #include <mujoco/mjexport.h>
+#include <mujoco/mjtnum.h>
+#include <mujoco/mjsan.h>  // IWYU pragma: keep
 #include <mujoco/mjxmacro.h>
 
 #ifdef __cplusplus

unity/Runtime/Bindings/MjBindings.cs

@@ -60,6 +60,7 @@ public const int mjNAUX = 10;
 public const int mjMAXTEXTURE = 1000;
 public const int mjMAXMATERIAL = 1000;
 public const bool THIRD_PARTY_MUJOCO_INCLUDE_MJSAN_H_ = true;
+public const bool ADDRESS_SANITIZER = true;
 public const bool THIRD_PARTY_MUJOCO_INCLUDE_MJSPEC_H_ = true;
 public const bool THIRD_PARTY_MUJOCO_INCLUDE_MJTHREAD_H_ = true;
 public const int mjMAXTHREAD = 128;