openzfs sys/types32.h: use abi_compat.h for time32_t

The time32_t typedef leaks into openzfs compilation environment
through sys/event.h.  Simultaneously, openzfs provides its own
definition that is only correct for amd64 on FreeBSD.

Try to fix it by using sys/abi_compat.h directly.  Since toolchain build
from the make buildworld uses host abi_compat.h, add a preprocessor
symbol __HAVE_TIME32_T to signal consumers that time32_t is typedef'ed.
If not defined, fall back to old and wrong time32_t, which is enough for
bootstraping toolchain.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D55135

sys/contrib/openzfs/include/os/freebsd/spl/sys/types32.h

@@ -30,9 +30,10 @@
 #ifndef _SPL_TYPES32_H
 #define	_SPL_TYPES32_H
 
+#include <sys/abi_compat.h>
+
 typedef uint32_t	caddr32_t;
 typedef int32_t	daddr32_t;
-typedef int32_t	time32_t;
 typedef uint32_t	size32_t;
 
 #endif  /* _SPL_TYPES32_H */

sys/contrib/openzfs/lib/libspl/include/sys/types32.h

@@ -63,7 +63,12 @@ typedef	uint32_t	dev32_t;
 typedef	int32_t		pid32_t;
 typedef	uint32_t	size32_t;
 typedef	int32_t		ssize32_t;
+#ifdef __FreeBSD__
+#include <sys/abi_compat.h>
+#endif
+#ifndef __HAVE_TIME32_T
 typedef	int32_t		time32_t;
+#endif
 typedef	int32_t		clock32_t;
 
 typedef struct timespec32 {

sys/sys/abi_compat.h

@@ -52,11 +52,16 @@ typedef struct {
 #endif
 } freebsd32_uint64_t;
 
-#ifdef __amd64__
+#if __SIZEOF_LONG__ == 8
+#if defined __amd64__
 typedef	__int32_t	time32_t;
 #else
 typedef	__int64_t	time32_t;
 #endif
+#else
+typedef	__int32_t	time32_t;
+#endif
+#define	__HAVE_TIME32_T
 
 #define	PTRIN(v)	(void *)(uintptr_t)(v)
 #define	PTROUT(v)	(uintptr_t)(v)