Make some preliminary porting changes.

These changes include:

  * hw_config.h: prevent referring to sysctlbyname on OpenBSD, as this
    is not available on all platforms.

  * transform.c: these stanzas referring to FreeBSD or Linux also apply
    to OpenBSD.

Author: 3405691582

src/shims/hw_config.h

@@ -187,12 +187,16 @@ _dispatch_hw_get_config(_dispatch_hw_config_t c)
 		name = "hw.activecpu"; break;
 	}
 #elif defined(__FreeBSD__)
-	 (void)c; name = "kern.smp.cpus";
+	(void)c; name = "kern.smp.cpus";
+#elif defined(__OpenBSD__)
+	(void)c;
 #endif
 	if (name) {
 		size_t valsz = sizeof(val);
+#if !defined(__OpenBSD__)
 		r = sysctlbyname(name, &val, &valsz, NULL, 0);
 		(void)dispatch_assume_zero(r);
+#endif
 		dispatch_assert(valsz == sizeof(uint32_t));
 	} else {
 #if HAVE_SYSCONF && defined(_SC_NPROCESSORS_ONLN)

src/transform.c

@@ -26,7 +26,7 @@
 #include <endian.h>
 #define OSLittleEndian __LITTLE_ENDIAN
 #define OSBigEndian __BIG_ENDIAN
-#elif defined(__FreeBSD__)
+#elif defined(__FreeBSD__) || defined(__OpenBSD__)
 #include <sys/endian.h>
 #define OSLittleEndian _LITTLE_ENDIAN
 #define OSBigEndian _BIG_ENDIAN
@@ -35,7 +35,7 @@
 #define OSBigEndian 4321
 #endif
 
-#if defined(__linux__) || defined(__FreeBSD__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__)
 #define OSSwapLittleToHostInt16 le16toh
 #define OSSwapBigToHostInt16 be16toh
 #define OSSwapHostToLittleInt16 htole16