fix build regression in sh-nofpu subarch due to missing symbol

commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 switched sigsetjmp to
use the new hidden ___setjmp symbol for setjmp, but the nofpu variant
of setjmp.s was not updated to match.

src/setjmp/sh-nofpu/setjmp.s

@@ -1,9 +1,12 @@
+.global ___setjmp
+.hidden ___setjmp
 .global __setjmp
 .global _setjmp
 .global setjmp
 .type   __setjmp, @function
 .type   _setjmp,  @function
 .type   setjmp,   @function
+___setjmp:
 __setjmp:
 _setjmp:
 setjmp: