undefined reference to `gt_ggc_mx_machine_function(void*)' `gt_pch_nx_machine_function(void*)'

[William Tambe]

I am porting GCC to a new 32bits cpu.

Any idea what could be the reason that I am getting undefined references to:
gt_ggc_mx_machine_function(void*)
gt_pch_nx_machine_function(void*)

Which macro or target-macro should I define to avoid such error ?

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gtype-desc.o: In function `gt_ggc_mx_function(void*)':
/home/user/Documents/gcc-8.2.0-build/gcc/gtype-desc.c:1621: undefined
reference to `gt_ggc_mx_machine_function(void*)'
gtype-desc.o: In function `gt_pch_nx_function(void*)':
/home/user/Documents/gcc-8.2.0-build/gcc/gtype-desc.c:5142: undefined
reference to `gt_pch_nx_machine_function(void*)'
collect2: error: ld returned 1 exit status
../../gcc-8.2.0/gcc/c/Make-lang.in:85: recipe for target 'cc1' failed
make[2]: *** [cc1] Error 1
make[2]: Leaving directory '/home/user/Documents/gcc-8.2.0-build/gcc'
Makefile:4246: recipe for target 'all-gcc' failed
make[1]: *** [all-gcc] Error 2
make[1]: Leaving directory '/home/user/Documents/gcc-8.2.0-build'
Makefile:883: recipe for target 'all' failed
make: *** [all] Error 2
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