The permisisons of the specs file in gcc-lib/amd64-unknown-openbsd6.0/4.2.1/ depend on the umask, thus set it explicitly to 444.
Moreover, headers and info files are installed with group wheel, which is different from all other headers and info files, so change that accordingly. Index: gnu/usr.bin/cc//cc/Makefile =================================================================== RCS file: /var/cvs/src/gnu/usr.bin/cc/cc/Makefile,v retrieving revision 1.6 diff -u -p -r1.6 Makefile --- gnu/usr.bin/cc//cc/Makefile 27 Sep 2016 19:30:01 -0000 1.6 +++ gnu/usr.bin/cc//cc/Makefile 5 Nov 2016 16:36:37 -0000 @@ -22,5 +22,6 @@ beforeinstall: afterinstall: ${.OBJDIR}/cc -dumpspecs > ${DESTDIR}${SPECDIR}/specs chown ${BINOWN}:${BINGRP} ${DESTDIR}${SPECDIR}/specs + chmod ${NONBINMODE} ${DESTDIR}${SPECDIR}/specs .include <bsd.prog.mk> Index: gnu/usr.bin/cc//doc/Makefile =================================================================== RCS file: /var/cvs/src/gnu/usr.bin/cc/doc/Makefile,v retrieving revision 1.1.1.1 diff -u -p -r1.1.1.1 Makefile --- gnu/usr.bin/cc//doc/Makefile 15 Oct 2009 20:50:20 -0000 1.1.1.1 +++ gnu/usr.bin/cc//doc/Makefile 8 Nov 2016 15:04:32 -0000 @@ -70,7 +70,7 @@ install: ${INFOF} install-info --quiet --section=${INFOSECTION} --entry=${INFOENTRY_${x}} \ ${x}.info ${DESTDIR}/usr/share/info/dir .endfor - ${INSTALL} -o ${BINOWN} -g ${LOCALEGRP} -m ${NONBINMODE} ${.ALLSRC} \ + ${INSTALL} -o ${DOCOWN} -g ${DOCGRP} -m ${DOCMODE} ${.ALLSRC} \ ${DESTDIR}/usr/share/info .include <bsd.prog.mk> Index: gnu/usr.bin/cc//include/Makefile =================================================================== RCS file: /var/cvs/src/gnu/usr.bin/cc/include/Makefile,v retrieving revision 1.12 diff -u -p -r1.12 Makefile --- gnu/usr.bin/cc//include/Makefile 16 Oct 2016 19:28:44 -0000 1.12 +++ gnu/usr.bin/cc//include/Makefile 8 Nov 2016 15:01:50 -0000 @@ -52,7 +52,7 @@ prereq: unwind.h .if !empty(INCS) install includes: ${INCS} - ${INSTALL} -C -o ${BINOWN} -g ${LOCALEGRP} -m ${NONBINMODE} ${.ALLSRC} \ + ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m ${NONBINMODE} ${.ALLSRC} \ ${DESTDIR}/usr/include .else install includes: Index: gnu/usr.bin/cc//libobjc/Makefile =================================================================== RCS file: /var/cvs/src/gnu/usr.bin/cc/libobjc/Makefile,v retrieving revision 1.3 diff -u -p -r1.3 Makefile --- gnu/usr.bin/cc//libobjc/Makefile 1 Jul 2013 14:22:08 -0000 1.3 +++ gnu/usr.bin/cc//libobjc/Makefile 8 Nov 2016 15:05:33 -0000 @@ -43,7 +43,7 @@ SRCS+= ${GENHDRS} includes: ${INCS} @test -d ${DESTDIR}/usr/include/objc || \ mkdir ${DESTDIR}/usr/include/objc - ${INSTALL} -C -o ${BINOWN} -g ${LOCALEGRP} -m ${NONBINMODE} ${.ALLSRC} \ + ${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m ${NONBINMODE} ${.ALLSRC} \ ${DESTDIR}/usr/include/objc .endif