FreeBSD ocaml support for aarch64

Hi,
lang/ocaml port is marked as broken on aarch64 and I would like to
contribute and have it fixed.

The broken reason is incorrect as of now:
BROKEN_aarch64=         Does not build: sh: as: not found

If I comment this line out, "as" is correctly found given the port
dependency from binutils:
BUILD_DEPENDS=  as:devel/binutils

The build process stops with:
ld: error: can't create dynamic relocation R_AARCH64_LDST64_ABS_LO12_NC
against symbol: camlUnix in readonly segment; recompile object files with
-fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
>>> defined in unix.a(unix.o)
>>> referenced by unix.ml:863
>>>               unix.o:(camlUnix__waitpid_non_intr_1853) in archive unix.a

ld: error: too many errors emitted, stopping now (use -error-limit=0 to see
all errors)
cc: error: linker command failed with exit code 1 (use -v to see invocation)
File "caml_startup", line 1:
Error: Error during linking
gmake[4]: *** [../Makefile:74: unix.cmxs] Error 2
gmake[4]: Leaving directory
'/wrkdirs/usr/ports/lang/ocaml/work/ocaml-4.05.0/otherlibs/unix'
gmake[3]: *** [Makefile:1055: otherlibrariesopt] Error 2
gmake[3]: Leaving directory
'/wrkdirs/usr/ports/lang/ocaml/work/ocaml-4.05.0'
gmake[2]: *** [Makefile:465: opt.opt] Error 2
gmake[2]: Leaving directory
'/wrkdirs/usr/ports/lang/ocaml/work/ocaml-4.05.0'
gmake[1]: *** [Makefile:531: world.opt] Error 2
gmake[1]: Leaving directory
'/wrkdirs/usr/ports/lang/ocaml/work/ocaml-4.05.0'
*** Error code 1

Stop.
make: stopped in /usr/ports/lang/ocaml

Trying to fix this issue by adding -fPIC to CONFIGURE_ARGS does nothing, in
the sense that the option actually adds -fPIC to ld args, but the error
remains.

So I went the other way and changed LDFLAGS as suggested by the error
message:
LDFLAGS_aarch64=        -Wl,-z,notext

In this case I hit an obscure error when making with make -j <numcpus>:
boot/ocamlrun ./ocamlopt -g -nostdlib -I stdlib -I otherlibs/dynlink
-strict-sequence -principal -absname -w +a-4-9-41-42-44-45-48 -warn-error A
-bin-annot -safe-string -strict-formats -I utils -I parsing -I typing -I
bytecomp -I middle_end -I middle_end/base_types -I asmcomp -I driver -I
toplevel -c middle_end/simplify_boxed_integer_ops.ml
File "/usr/ports/lang/ocaml/work/ocaml-4.05.0/_none_", line 1:
Warning 58: no cmx file was found in path for module Compilenv, and its
interface was not compiled with -opaque
boot/ocamlrun ./ocamlopt -g -nostdlib -I stdlib -I otherlibs/dynlink
-strict-sequence -principal -absname -w +a-4-9-41-42-44-45-48 -warn-error A
-bin-annot -safe-string -strict-formats -I utils -I parsing -I typing -I
bytecomp -I middle_end -I middle_end/base_types -I asmcomp -I driver -I
toplevel -c middle_end/simplify_primitives.ml
File "/usr/ports/lang/ocaml/work/ocaml-4.05.0/asmcomp/selection.ml", line 1:
Error: Some fatal warnings were triggered (1 occurrences)
gmake[4]: *** [Makefile:1270: asmcomp/selection.cmx] Error 2
gmake[4]: *** Waiting for unfinished jobs....
gmake[4]: Leaving directory '/usr/ports/lang/ocaml/work/ocaml-4.05.0'
gmake[3]: *** [Makefile:464: opt.opt] Error 2
gmake[3]: Leaving directory '/usr/ports/lang/ocaml/work/ocaml-4.05.0'
gmake[2]: *** [Makefile:531: world.opt] Error 2
gmake[2]: Leaving directory '/usr/ports/lang/ocaml/work/ocaml-4.05.0'
*** [do-build] Error code 1

make[1]: stopped in /usr/ports/lang/ocaml
1 error

make[1]: stopped in /usr/ports/lang/ocaml
*** [stage] Error code 2

make: stopped in /usr/ports/lang/ocaml
1 error

make: stopped in /usr/ports/lang/ocaml

If I continue without -j, ld fails with a similar error:
ld: error: relocation R_AARCH64_LDST64_ABS_LO12_NC cannot be used against
symbol camlUnix; recompile with -fPIC

Note: -fPIC is enabled.

I am stuck, can someone suggest how to proceed? Thank you.

BR,