diff -Paur --no-dereference -- xz.upstream/build-aux/config.sub xz/build-aux/config.sub
--- xz.upstream/build-aux/config.sub
+++ xz/build-aux/config.sub
@@ -1373,7 +1373,7 @@
 	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
 	      | -sym* | -kopensolaris* | -plan9* \
 	      | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
-	      | -aos* | -aros* \
+	      | -aos* | -aros* | -sortix* \
 	      | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
 	      | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
 	      | -hiux* | -386bsd* | -knetbsd* | -mirbsd* | -netbsd* \
diff -Paur --no-dereference -- xz.upstream/configure xz/configure
--- xz.upstream/configure
+++ xz/configure
@@ -18313,6 +18313,7 @@
 
 #if defined(_WIN32) || defined(__CYGWIN__) || defined(__OS2__) \
 		|| defined(__DJGPP__) || defined(__VMS) \
+		|| defined(__sortix__) \
 		|| defined(AMIGA) || defined(__AROS__)
 int main(void) { return 0; }
 #else
diff -Paur --no-dereference -- xz.upstream/src/common/tuklib_physmem.c xz/src/common/tuklib_physmem.c
--- xz.upstream/src/common/tuklib_physmem.c
+++ xz/src/common/tuklib_physmem.c
@@ -67,6 +67,11 @@
 // This sysinfo() is Linux-specific.
 #elif defined(TUKLIB_PHYSMEM_SYSINFO)
 #	include <sys/sysinfo.h>
+
+// Sortix
+#elif defined(__sortix__)
+#	include <unistd.h>
+
 #endif
 
 
@@ -197,6 +202,10 @@
 	struct sysinfo si;
 	if (sysinfo(&si) == 0)
 		ret = (uint64_t)si.totalram * si.mem_unit;
+#elif defined(__sortix__)
+	size_t ret_size_t;
+	memstat(NULL, &ret_size_t);
+	ret = ret_size_t;
 #endif
 
 	return ret;