PIC24 XC16 Compiler has no __builtin_ffs

I am having difficulty porting to the PIC24 XC16 compiler.
The error is:
undefined reference to `___clzhi2
I believe this is because it has no “__builtin_ffs” or __builtin_clz" instructions used in “lv_tlsf.c”
How do I overcome this challenge ?

Additional note:
It looks like the lv_tlsf.c is not defaulting to the generic implementation.
This is regarding version - LVGL v8.3.7

Yep - that was it.
Had to add , #if defined (GNUC) && (GNUC > 3 || (GNUC == 3 && GNUC_MINOR >= 4))
&& defined (GNUC_PATCHLEVEL) && !defined(XC16)

to the “lv_tlfs.c” file.