diff --git a/lib/libsys/syscalls.map b/lib/libsys/syscalls.map
--- a/lib/libsys/syscalls.map
+++ b/lib/libsys/syscalls.map
@@ -353,8 +353,6 @@
 	__sys_aio_cancel;
 	_aio_error;
 	__sys_aio_error;
-	_yield;
-	__sys_yield;
 	_mlockall;
 	__sys_mlockall;
 	_munlockall;
diff --git a/sys/tools/makesyscalls.lua b/sys/tools/makesyscalls.lua
--- a/sys/tools/makesyscalls.lua
+++ b/sys/tools/makesyscalls.lua
@@ -924,6 +924,10 @@
 		    config.syscallprefix, funcalias, sysnum))
 		write_line("sysmk", string.format(" \\\n\t%s.o",
 		    funcalias))
+		-- yield has never been exposed as a syscall
+		if funcalias == "yield" then
+			return
+		end
 		if funcalias ~= "exit" and funcalias ~= "vfork" then
 			write_line("libsysmap", string.format("\t_%s;\n",
 			    funcalias))