Remove some library functions for no-JIT/no-FFI builds.

src/lj_errmsg.h

@@ -102,7 +102,11 @@ ERRDEF(STRFMTW,	"invalid format (width or precision too long)")
 ERRDEF(STRGSRV,	"invalid replacement value (a %s)")
 ERRDEF(BADMODN,	"name conflict for module " LUA_QS)
 #if LJ_HASJIT
+#if LJ_TARGET_X86ORX64
 ERRDEF(NOJIT,	"JIT compiler disabled, CPU does not support SSE2")
+#else
+ERRDEF(NOJIT,	"JIT compiler disabled")
+#endif
 #elif defined(LJ_ARCH_NOJIT)
 ERRDEF(NOJIT,	"no JIT compiler for this architecture (yet)")
 #else