I want to cross compile a MIPS FreeBSD image on X86 FreeBSD
But I have some small problems. Can you give me some advice
Thanks

Basic information:
Reference website:https://wiki.freebsd.org/mips
Source code:https://github.com/freebsd/freebsd.git
Script:https://github.com/freebsd/freebsd-wifi-build.git
My FreeBSD version:12.1-RELEASE(X86-64)
My Shell:/bin/sh

When I executed the following command, I had a problem
../freebsd-wifi-build/build/bin/build carambola2 buildworld buildkernel installworld installkernel distribution

Error information:
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 331: Unknown keyword "
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 331: improper shell specification
make: Fatal errors encountered -- cannot continue
make: stopped in /usr/home/freebsd_build/pfsense/freebsd

Complete information:

_$ ../freebsd-wifi-build/build/bin/build carambola2 buildworld buildkernel installworld installkernel distribution
Checking - u-boot-tools .. OK.
Checking - lzma .. OK.
Checking - perl5 .. OK.
Checking - rsync .. OK.
Checking - mips-xtoolchain-gcc .. OK.
*** Configuration file : carambola2
*** Base configuration : mips_ap
*** Platform : mips_ap
Build list: buildworld buildkernel installworld installkernel distribution
*** Target : buildworld
MAKEOBJDIRPREFIX: /home/freebsd_build/pfsense/freebsd/../obj/mips_ap/
*** Stage : buildworld
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 21: Unassociated shell command "UNIFIED_OBJDIR"
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 31: Unassociated shell command "DIRDEPS_BUILD
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 32: Unassociated shell command "DIRDEPS_CACHE"
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 35: Unassociated shell command "AUTO_OBJ/DIRDEPS_BUILD
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 36: Unassociated shell command "META_MODE/DIRDEPS_BUILD
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 37: Unassociated shell command "STAGING/DIRDEPS_BUILD
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 38: Unassociated shell command "SYSROOT/DIRDEPS_BUILD"
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 41: Unassociated shell command "${__DEFAULT_NO_OPTIONS}
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 42: Unassociated shell command "${__DEFAULT_YES_OPTIONS}
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 43: Unassociated shell command "${_DEFAULT_DEPENDENT_OPTIONS:H}"
make: "/usr/home/freebsd_build/pfsense/freebsd/Makefile.sys.inc" line 11: Malformed conditional (${MK_DIRDEPS_BUILD} == "no")
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/src.sys.obj.mk" line 35: Malformed conditional (${MK_UNIFIED_OBJDIR} == "no" && ${MK_DIRDEPS_BUILD} == "no")
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/src.sys.obj.mk" line 79: Malformed conditional (${MK_DIRDEPS_BUILD} == "no")
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 55: Malformed conditional (${MK_META_MODE} == "yes" && defined(.MAKEFLAGS) && ${.MAKEFLAGS:M-B})
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 59: Malformed conditional (${MK_DIRDEPS_BUILD} == "yes")
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 117: Malformed conditional (${MK_AUTO_OBJ} == "yes")
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/local.sys.mk" line 3: Malformed conditional (${MK_DIRDEPS_BUILD} == "yes" || ${MK_META_MODE} == "yes")
"ake: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 331: Unknown keyword "
make: "/usr/home/freebsd_build/pfsense/freebsd/share/mk/sys.mk" line 331: improper shell specification
make: Fatal errors encountered -- cannot continue
make: stopped in /usr/home/freebsd_build/pfsense/freebsd

=========================================================
Here's the order I executed before

1. Install various prerequisites

${SUDO} pkg install fakeroot gmake bison dialog4ports git wget subversion lzma u-boot-tools libtool
2. Create a working directory

3. Within that directory, make a copy of the freebsd sources, and freebsd-wifi-build.
   For example, using github:
   git clone https://github.com/freebsd/freebsd.git
git clone https://github.com/freebsd/freebsd-wifi-build.git

4. Prepare a user customisation script
   Note, by default the kernel in /tftpboot will be read-only which means successive installkernel
   will fail unless it is moved out of the way, or the option X_FORCE_TFTPCP=YES is used

   echo 'X_FORCE_TFTPCP=YES' > ~/.freebsd-wifi-build-settings.cfg

5. Build the userland and kernel and the staging tree
   ../freebsd-wifi-build/build/bin/build carambola2 buildworld buildkernel installworld installkernel distribution `

=============================================================
sys.mk：

.ifndef WITHOUT_SHELL_ERRCTL
__MAKE_SHELL?=/bin/sh
SHELL: name=sh \ #331line
quiet="set -" echo="set -v" filter="set -"
hasErrCtl=yes check="set -e" ignore="set +e"
echoFlag=v errFlag=e
path=${__MAKE_SHELL}
.endif

====================================================
Can you give me some suggestions to build a FreeBSD image of MIPS.
Thank you.