This used to be necessary in the gcc 2.95 days. Nowadays nothing in base or X uses it.
Index: share/mk/bsd.own.mk =================================================================== RCS file: /OpenBSD/src/share/mk/bsd.own.mk,v retrieving revision 1.184 diff -u -p -r1.184 bsd.own.mk --- share/mk/bsd.own.mk 18 Apr 2017 14:03:08 -0000 1.184 +++ share/mk/bsd.own.mk 6 Jun 2017 19:12:04 -0000 @@ -129,10 +129,6 @@ PICFLAG?=-fPIC PICFLAG?=-fpic .endif -.if ${MACHINE_ARCH} == "sparc64" -ASPICFLAG=-KPIC -.endif - .if ${MACHINE_ARCH} == "alpha" || ${MACHINE_ARCH} == "powerpc" || \ ${MACHINE_ARCH} == "sparc64" # big PIE