You need this extra chunk for your diff to work. With that, the built instbin binary appears to behave as expected on hppa.
Index: distrib/special/Makefile.inc =================================================================== RCS file: /OpenBSD/src/distrib/special/Makefile.inc,v retrieving revision 1.9 diff -u -p -u -p -r1.9 Makefile.inc --- distrib/special/Makefile.inc 10 Mar 2021 22:52:28 -0000 1.9 +++ distrib/special/Makefile.inc 30 Dec 2022 06:14:37 -0000 @@ -1,7 +1,7 @@ # options for all the directories below COPTS+=-Oz -fno-stack-protector -COPTS+=-fno-unwind-tables -fno-asynchronous-unwind-tables +COPTS+=-fno-unwind-tables -fno-asynchronous-unwind-tables -fno-common MAN= LDSTATIC=-static NOPIE=
