Failed buildworld buildkernel: /usr/obj/. . ./arm.armv7/tmp/usr/bin/ld: cannot find -lgcc_s for all_subdir_lib/libdl (a build race?)

I tried to amd64 -> armv7 cross build head -r332861 and got an error about
-lgcc_s not being found. I backed off to -r332858 for other reasons (powerpc*
related). Retrying the armv7 build then worked.

I had first upgraded the amd64 context the first time and had backed off amd64
first the second time. (The builds are explicit about -mcpu=cortext-a7 .)

(When I think about it, I tend to check https://ci.freebsd.org to pick a
version likely to build for the variations that I play with. But armv7
is not covered by https://ci.freebsd.org . armv7 variations are missing from
the report for -r332796's snapshots. But I'm not aware of anything around
that indicates why variations ended up missing for snapshots.)

Below is the error report that shows the message and the _ERROR_CMD that
was involved. I have no direct clue if it is because of a race relative
to gcc_s availability or not. The context involved WITH_META_MODE=yes and
-j28 .

I do not see anything in -r332859 to -r332861 that would suggest anything
but a race as a relevant difference, where a re-try found gcc_s already
available.

--- all_subdir_lib/libdl ---
/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/usr/bin/ld: cannot find -lgcc_s
--- all_subdir_lib/libbsm ---
Building /usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/lib/libbsm/bsm_notify.o
--- sbin/ipf/libipf__L ---
Building /usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/sbin/ipf/libipf/printiphdr.o
--- lib__L ---
--- all_subdir_lib/libdl ---
cc: error: linker command failed with exit code 1 (use -v to see invocation)
--- all_subdir_lib/libdevinfo ---
--- libdevinfo.a ---
building static devinfo library
--- kerberos5/lib__L ---
Building /usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/kerberos5/lib/libkadm5srv/set_keys.o
--- lib__L ---
--- all_subdir_lib/libdl ---
*** [libdl.so.1.full] Error code 1

make[5]: stopped in /usr/src/lib/libdl
.ERROR_TARGET='libdl.so.1.full'
.ERROR_META_FILE='/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/lib/libdl/libdl.so.1.full.meta'
.MAKE.LEVEL='5'
MAKEFILE=''
.MAKE.MODE='meta missing-filemon=yes missing-meta=yes silent=yes verbose'
_ERROR_CMD='_at_echo building shared library libdl.so.1; _at_rm -f libdl.so.1 libdl.so; cc -mcpu=cortex-a7 -target armv7-gnueabihf-freebsd12.0 --sysroot=/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp -B/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/usr/bin  -Wl,-F,libc.so.7 -Wl,--version-script=Version.map   -shared -Wl,-x -Wl,--fatal-warnings -Wl,--warn-shared-textrel  -o libdl.so.1.full -Wl,-soname,libdl.so.1  `NM='nm' NMFLAGS='' lorder dlfcn.pico |  tsort -q` ;'
.CURDIR='/usr/src/lib/libdl'
.MAKE='make'
.OBJDIR='/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/lib/libdl'
.TARGETS='all'
DESTDIR='/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp'
LD_LIBRARY_PATH=''
MACHINE='arm'
MACHINE_ARCH='armv7'
MAKEOBJDIRPREFIX=''
MAKESYSPATH='/usr/src/share/mk'
MAKE_VERSION='20180222'
PATH='/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/legacy/usr/sbin:/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/legacy/usr/bin:/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/legacy/bin:/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/usr/sbin:/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7/tmp/usr/bin:/sbin:/bin:/usr/sbin:/usr/bin'
SRCTOP='/usr/src'
OBJTOP='/usr/obj/armv7_clang/arm.armv7/usr/src/arm.armv7'
.MAKE.MAKEFILES='/usr/src/share/mk/sys.mk /usr/src/share/mk/local.sys.env.mk /usr/src/share/mk/src.sys.env.mk /root/src.configs/src.conf.armv7-clang-bootstrap.amd64-host /usr/src/share/mk/bsd.mkopt.mk /usr/src/share/mk/src.sys.obj.mk /usr/src/share/mk/auto.obj.mk /usr/src/share/mk/bsd.suffixes.mk /root/src.configs/make.conf /usr/src/share/mk/local.sys.mk /usr/src/share/mk/src.sys.mk /dev/null /usr/src/lib/libdl/Makefile /usr/src/share/mk/bsd.lib.mk /usr/src/share/mk/bsd.init.mk /usr/src/share/mk/bsd.opts.mk /usr/src/share/mk/bsd.cpu.mk /usr/src/share/mk/local.init.mk /usr/src/share/mk/src.init.mk /usr/src/lib/libdl/../Makefile.inc /usr/src/share/mk/bsd.own.mk /usr/src/share/mk/bsd.compiler.mk /usr/src/share/mk/bsd.linker.mk /usr/src/share/mk/bsd.libnames.mk /usr/src/share/mk/src.libnames.mk /usr/src/share/mk/src.opts.mk /usr/src/share/mk/bsd.symver.mk /usr/src/share/mk/bsd.nls.mk /usr/src/share/mk/bsd.files.mk /usr/src/share/mk/bsd.incs.mk /usr/src/share/mk/bsd.confs.mk /usr/src/share/mk/bsd.links.mk /usr/src/share/mk/bsd.dep.mk /usr/src/share/mk/bsd.clang-analyze.mk /usr/src/share/mk/bsd.obj.mk /usr/src/share/mk/bsd.subdir.mk /usr/src/share/mk/bsd.sys.mk'
.PATH='. /usr/src/lib/libdl /usr/src/lib/libc/gen'
1 error

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)