Tidy up claimed supported CPUs and OSes.

 * Remove arbitrary mention of certain endianness and bitness variants;
   it's enough to say that applicable variants are expected to work.
 * List RISC-V (known to work, being tested).
 * List SuperH and M88K (code exists, unknown status, like M68K).
 * De-list VAX and remove code (known not to work).
 * Remove stray trace of Alpha (support was removed years ago).
 * List illumos, DragonFlyBSD (known to work, being tested).
 * No need to single Windows out by listing a specific version, when we
   don't do that for other OSes; it's enough to say that we support
   current versions of the listed OSes (when 16 ships, that'll be
   Windows 10+).

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Greg Stark <stark@mit.edu>
Discussion: https://postgr.es/m/CA%2BhUKGKk7NZO1UnJM0PyixcZPpCGqjBXW_0bzFZpJBGAf84XKg%40mail.gmail.com

Author: macdice

contrib/pgcrypto/crypt-blowfish.c

@@ -41,7 +41,7 @@
 #ifdef __i386__
 #define BF_ASM				0	/* 1 */
 #define BF_SCALE			1
-#elif defined(__x86_64__) || defined(__alpha__) || defined(__hppa__)
+#elif defined(__x86_64__) || defined(__hppa__)
 #define BF_ASM				0
 #define BF_SCALE			1
 #else

doc/src/sgml/installation.sgml

@@ -2125,18 +2125,19 @@ export MANPATH
 
   <para>
    In general, <productname>PostgreSQL</productname> can be expected to work on
-   these CPU architectures: x86, x86_64, PowerPC,
-   PowerPC 64, S/390, S/390x, Sparc, Sparc 64, ARM, MIPS, MIPSEL,
-   and PA-RISC.  Code support exists for M68K, M32R, and VAX, but these
+   these CPU architectures: x86, PowerPC, S/390, Sparc, ARM, MIPS, RISC-V,
+   and PA-RISC, including
+   big-endian, little-endian, 32-bit, and 64-bit variants where applicable.
+   Code support exists for M68K, M88K, M32R, and SuperH, but these
    architectures are not known to have been tested recently.  It is often
    possible to build on an unsupported CPU type by configuring with
    <option>--disable-spinlocks</option>, but performance will be poor.
   </para>
 
   <para>
-   <productname>PostgreSQL</productname> can be expected to work on these operating
-   systems: Linux (all recent distributions), Windows (10 and later),
-   FreeBSD, OpenBSD, NetBSD, macOS, AIX, and Solaris.
+   <productname>PostgreSQL</productname> can be expected to work on current
+   versions of these operating systems: Linux, Windows,
+   FreeBSD, OpenBSD, NetBSD, DragonFlyBSD, macOS, AIX, Solaris, and illumos.
    Other Unix-like systems may also work but are not currently
    being tested.  In most cases, all CPU architectures supported by
    a given operating system will work.  Look in

src/include/storage/s_lock.h

@@ -548,36 +548,6 @@ tas(volatile slock_t *lock)
 #endif	 /* __m88k__ */
 
 
-/*
- * VAXen -- even multiprocessor ones
- * (thanks to Tom Ivar Helbekkmo)
- */
-#if defined(__vax__)
-#define HAS_TEST_AND_SET
-
-typedef unsigned char slock_t;
-
-#define TAS(lock) tas(lock)
-
-static __inline__ int
-tas(volatile slock_t *lock)
-{
-	register int	_res;
-
-	__asm__ __volatile__(
-		"	movl 	$1, %0			\n"
-		"	bbssi	$0, (%2), 1f	\n"
-		"	clrl	%0				\n"
-		"1: \n"
-:		"=&r"(_res), "+m"(*lock)
-:		"r"(lock)
-:		"memory");
-	return _res;
-}
-
-#endif	 /* __vax__ */
-
-
 #if defined(__mips__) && !defined(__sgi)	/* non-SGI MIPS */
 #define HAS_TEST_AND_SET