release.sh: sh: head: not found \n Unable to determine linker type from LD=ld

Hi,

My 12.0-CURRENT r320259 host is unable to complete a release.sh build of
a generic world:

[...]
./usr.sbin/fstyp missing (created)                                       
./usr.sbin/makefs missing (created)                                      
./usr.sbin/newsyslog missing (created)
./usr.sbin/nmtree missing (created)
./usr.sbin/pw missing (created)
./usr.sbin/rpcbind missing (created)                                     
./usr.sbin/sa missing (created)                                          
mtree -deU -i -f /usr/src/etc/mtree/BSD.sendmail.dist -p
//usr/obj/usr/src/release/dist/base/                                     
./var/spool/clientmqueue missing (created)                               
install -l s usr/src/sys //usr/obj/usr/src/release/dist/base/sys         
cd //usr/obj/usr/src/release/dist/base/usr/share/man;  for mandir in
man*; do  install -l s ../$mandir 
//usr/obj/usr/src/release/dist/base/usr/share/man/en.ISO8859-1/; 
install -l s ../$mandir 
//usr/obj/usr/src/release/dist/base/usr/share/man/en.UTF-8/;  done
cd //usr/obj/usr/src/release/dist/base/usr/share/openssl/man;  for
mandir in man*; do  install -l s ../$mandir 
//usr/obj/usr/src/release/dist/base/usr/share/openssl/man/en.ISO8859-1/;
 done
set - `grep "^[a-zA-Z]" /usr/src/etc/man.alias`;  while [ $# -gt 0 ] ;
do  install -l s "$2"
"//usr/obj/usr/src/release/dist/base/usr/share/man/$1";  if [ "yes" !=
"no" ]; then  install -l s "$2" 
"//usr/obj/usr/src/release/dist/base/usr/share/openssl/man/$1";  fi; 
shift; shift;  done
set - `grep "^[a-zA-Z]" /usr/src/etc/nls.alias`;  while [ $# -gt 0 ] ;
do  install -l s "$2"
"//usr/obj/usr/src/release/dist/base/usr/share/nls/$1";  shift; shift; 
done      
cd /usr/src; COMPILER_VERSION=40000  COMPILER_FEATURES=c++11 
COMPILER_TYPE=clang  COMPILER_FREEBSD_VERSION=1200006
MAKEOBJDIRPREFIX=/usr/obj  MACHINE_ARCH=amd64  MACHINE=amd64  CPUTYPE=
CC="cc -target x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/usr/src/tmp
-B/usr/obj/usr/src/tmp/usr/bin" CXX="c++  -target
x86_64-unknown-freebsd12.0 --sysroot=/usr/
obj/usr/src/tmp -B/usr/obj/usr/src/tmp/usr/bin"  CPP="cpp -target
x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/usr/src/tmp
-B/usr/obj/usr/src/tmp/usr/bin"  AS="as" AR="ar" LD="ld" LLVM_LINK="" 
NM=nm OBJCOPY="objcopy"  RANLIB=ranlib STRINGS=  SIZE="size"
PATH=/usr/obj/usr/src/tmp/legacy/usr/sbin:/usr/obj/usr/src/tmp/legacy/usr/bin:/usr/obj/usr/src/t
mp/legacy/bin:/usr/obj/usr/src/tmp/usr/sbin:/usr/obj/usr/src/tmp/usr/bin:/tmp/install.hb5C6cay
 LD_LIBRARY_PATH=/tmp/install.hb5C6cay 
PATH_LOCALE=/tmp/install.hb5C6cay/locale make -f Makefile.inc1   
__MAKE_SHELL=/tmp/install.hb5C6cay/sh redistribute; 
COMPILER_VERSION=40000  COMPILER_FEATURES=c++11  COMPILER_TYPE=clang 
COMPILER_FREEBSD_VERSION=120
0006 MAKEOBJDIRPREFIX=/usr/obj  MACHINE_ARCH=amd64  MACHINE=amd64 
CPUTYPE= CC="cc -target x86_64-unknown-freebsd12.0
--sysroot=/usr/obj/usr/src/tmp -B/usr/obj/usr/src/tmp/usr/bin" CXX="c++ 
-target x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/usr/src/tmp
-B/usr/obj/usr/src/tmp/usr/bin"  CPP="cpp -target
x86_64-unknown-freebsd12.0 --sysroot=/usr/obj
/usr/src/tmp -B/usr/obj/usr/src/tmp/usr/bin"  AS="as" AR="ar" LD="ld"
LLVM_LINK=""  NM=nm OBJCOPY="objcopy"  RANLIB=ranlib STRINGS= 
SIZE="size"
PATH=/usr/obj/usr/src/tmp/legacy/usr/sbin:/usr/obj/usr/src/tmp/legacy/usr/bin:/usr/obj/usr/src/tmp/legacy/bin:/usr/obj/usr/src/tmp/usr/sbin:/usr/obj/usr/src/tmp/usr/bin:/tmp/install.hb5C6cay
 LD_LIBRARY_PATH
=/tmp/install.hb5C6cay  PATH_LOCALE=/tmp/install.hb5C6cay/locale rm -rf
/tmp/install.hb5C6cay
sh: head: not found                                                      
make[4]: "/usr/src/share/mk/bsd.linker.mk" line 42: Unable to determine
linker type from LD=ld                                                   
*** Error code 1                                                         

Stop.
make[3]: stopped in /usr/src                                             
*** Error code 1                                                         

Stop.
make[2]: stopped in /usr/src                                             
*** Error code 1                                                         

Stop.
make[1]: stopped in /usr/src/release                                     
*** Error code 1                                                         

Stop.
make: stopped in /usr/src/release

Interesting how head(1) is not found, it does exists:
$ lsc -i /scratch/generic/usr/bin/head
279252 /scratch/generic/usr/bin/head

To good health,
Alastair