How to link a C library to an Assembly library on Mac with clang - macos

Question

I have this in my C library:
myc:
#clang -I . -dynamiclib \
-undefined dynamic_lookup \
-o myc.dylib myc.c
.PHONY: myc
And this in my assembly library:
buildasm:
#nasm -f macho64 myasm.asm
#clang -o myasm myasm.o myc.dylib
# #ld -macosx_version_min 10.13.0 \
# -lSystem -o myasm \
# myasm.o
#./myasm
.PHONY: buildasm
I would like to then have a third either assembly or C project which loads the assembly library. But I can't get this C -> assembly working. I also don't have dyld the "dynamic loader" on Mac installed, so if possible I would prefer not to install any special tools, but if required I would like to know how to do the linking with the tool.
If I make the buildasm into this:
buildasm:
#nasm -f macho64 myasm.asm
#ld -macosx_version_min 10.13.0 \
-lSystem -o myasm \
myasm.o myc.dylib
#./myasm
.PHONY: buildasm
it compiles without any errors, but when it runs with ./myasm it gives:
Undefined symbols for architecture x86_64:
"my_c_function", referenced from:
start in myasm.o
ld: symbol(s) not found for inferred architecture x86_64
If I do this basically in asm:
extern my_c_function
start:
call my_c_function
And something like this in C:
extern void my_c_function() {
}
Wondering what would make this work.