CURRENT: cross compiling 12-STABLE failure in: bin/cp/utils.c:517:14: error: member reference base type 'void' is not a structure or union

For a couple of weeks now cross-compiling 12-STBALE on CURRENT fails
due to an compiler error in bin/cp/utils.c, see details below.

At this moment, CURRENT is at FreeBSD 13.0-CURRENT #39 r366364: Fri Oct
 2 17:51:39 CEST 2020 amd64 and the sources for 12-STABLE are at
revision 366437.

The compilation environment is the NanoBSD environment of the CURRENT
running host.

A similar constellation of host and cross-compiled target (regarding OS
versions, the hardware platform is slightly different, for the record)
works: running a simple, well known "make" builds 12-STABLE without
problems.

I tried to build NanoBSD in a vanilla state (without conf files for
WITH/WITHOUT tags), but the failure is always the same.

Can someone help or give some hints where to look for the reason of th
miscompilation?

Thanks in advance,

oh

[...]
--- CP1026%UCS.mps ---
/pool/nanobsd/amd64/ALERICH_12-STABLE_amd64/pool/sources/12-STABLE/src/amd64.amd64/usr.bin/mkcsmapper_static/mkcsmapper_static
-o CP1026%UCS.mps
/pool/sources/12-STABLE/src/share/i18n/csmapper/CP/CP1026%UCS.src ---
UCS%CP1026.mps ---
/pool/nanobsd/amd64/ALERICH_12-STABLE_amd64/pool/sources/12-STABLE/src/amd64.amd64/usr.bin/mkcsmapper_static/mkcsmapper_static
-o UCS%CP1026.mps
/pool/sources/12-STABLE/src/share/i18n/csmapper/CP/UCS%CP1026.src ---
all_subdir_rescue ---
/pool/sources/12-STABLE/src/bin/cp/utils.c:517:14: error: member
reference base type 'void' is not a structure or union aclp =
&acl->ats_acl; ~~~^ ~~~~~~~
/pool/sources/12-STABLE/src/bin/cp/utils.c:518:11: error: incomplete
definition of type 'struct acl' if (aclp->acl_cnt != 0 &&
aclsetf(dest_dir, ~~~~^
/pool/sources/12-STABLE/src/bin/cp/utils.c:468:9: note: forward
declaration of 'struct acl' struct acl *aclp; ^ 2 errors generated. ***
[/pool/sources/12-STABLE/src/bin/cp/utils.o] Error code 1

make[6]: stopped in
/pool/nanobsd/amd64/ALERICH_12-STABLE_amd64/pool/sources/12-STABLE/src/amd64.amd64/rescue/rescue
1 error

make[6]: stopped in
/pool/nanobsd/amd64/ALERICH_12-STABLE_amd64/pool/sources/12-STABLE/src/amd64.amd64/rescue/rescue
*** [rescue] Error code 2

make[5]: stopped in /pool/sources/12-STABLE/src/rescue/rescue
1 error

make[5]: stopped in /pool/sources/12-STABLE/src/rescue/rescue
--- all_subdir_lib ---
--- all_subdir_share ---