gallium,util: undef ALIGN on FreeBSD to prevent name clash

Some rare headers like ipc/shm and pthread_np cause
machine/param.h to be included which defines a macro called ALIGN.

Signed-off-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3559>
(cherry picked from commit 29e2a3b8f5)

.pick_status.json

@@ -2470,7 +2470,7 @@
         "description": "gallium,util: undef ALIGN on FreeBSD to prevent name clash",
         "nominated": false,
         "nomination_type": null,
-        "resolution": 4,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": null
     },

src/gallium/winsys/sw/dri/dri_sw_winsys.c

@@ -29,6 +29,12 @@
 #ifdef HAVE_SYS_SHM_H
 #include <sys/ipc.h>
 #include <sys/shm.h>
+#ifdef __FreeBSD__
+/* sys/ipc.h -> sys/_types.h -> machine/param.h
+ * - defines ALIGN which clashes with our ALIGN
+ */
+#undef ALIGN
+#endif
 #endif
 
 #include "pipe/p_compiler.h"

src/util/u_thread.h

@@ -45,6 +45,10 @@
 #endif
 
 #ifdef __FreeBSD__
+/* pthread_np.h -> sys/param.h -> machine/param.h
+ * - defines ALIGN which clashes with our ALIGN
+ */
+#undef ALIGN
 #define cpu_set_t cpuset_t
 #endif