Harfbuzz version 7.0.1 does not appear to compile on AIX. Bumping to 7.1.0 fixes one issue, but another issue is present after fixing that.

The first build error is:
Error while processing /home/hotspot/openjdk/jdk-deepa/src/java.desktop/share/native/libharfbuzz/hb-aat-map.cc.
In file included from /home/hotspot/openjdk/jdk-deepa/src/java.desktop/share/native/libharfbuzz/hb-buffer.cc:30:
In file included from /home/hotspot/openjdk/jdk-deepa/src/java.desktop/share/native/libharfbuzz/hb-buffer.hh:33:
In file included from /home/hotspot/openjdk/jdk-deepa/src/java.desktop/share/native/libharfbuzz/hb.hh:513:
/home/hotspot/openjdk/jdk-deepa/src/java.desktop/share/native/libharfbuzz/hb-algs.hh:882:10: error: 1540-2993 The builtin "__builtin_mul_overflow" is not supported.
  return __builtin_mul_overflow (count, size, result);

Then:

=== Output from failing command(s) repeated here ===
* For target support_native_java.desktop_libfontmanager_hb-subset.o:
In file included from /home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-subset.cc:27:
In file included from /home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/OT/Color/COLR/../../../hb.hh:522:
/home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-iter.hh:372:23: error: no matching function for call to object of type 'struct (anonymous struct at /home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-algs.hh:414:1)'
            decltype (hb_get (hb_declval (Proj), *hb_declval (Iter)))>
                      ^~~~~~
/home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-map.hh:346:5: note: in instantiation of template class 'hb_map_iter_t<hb_filter_iter_t<hb_array_t<hb_hashmap_t<hb_array_t<const char>, unsigned int, true>::item_t>, bool (hb_hashmap_t<hb_array_t<const char>, unsigned int, true>::item_t::*)() const, (anonymous struct at /home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-algs.hh:202:1) &, nullptr>, const char *, hb_function_sortedness_t::NOT_SORTED, nullptr>' requested here
    + keys_ref ()
    ^
/home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-ot-post-table-v2subset.hh:81:44: note: in instantiation of template class 'hb_hashmap_t<hb_array_t<const char>, unsigned int, true>' requested here
  hb_hashmap_t<hb_bytes_t, uint32_t, true> glyph_name_to_new_index;
                                           ^
/home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-algs.hh:440:3: note: candidate template ignored: substitution failure [with Proj = const char *, Val = hb_hashmap_t<hb_array_t<const char>, unsigned int, true>::item_t &]: no matching member function for call to 'impl'
  operator () (Proj&& f, Val &&v) const HB_AUTO_RETURN
  ^
In file included from /home/hotspot/openjdk/jdk-tyler/src/java.desktop/share/native/libharfbuzz/hb-subset.cc:27:
   ... (rest of output omitted)

* All command lines available in /home/hotspot/openjdk/jdk-tyler/build/aix-ppc64-server-fastdebug/make-support/failure-logs.
=== End of repeated output ===