OpenJDK 8, and 17+ fail to compile on Alpine-linux using gcc 11.2.1.

jdk17+:
hotspot/share/gc/shenandoah/shenandoahBarrierSet.inline.hpp:219:62: error: invalid cast from type 'std::nullptr_t' to type 'oopDesc**'

jdk8:
hotspot/src/share/vm/adlc/dict2.cpp:286:17: error: ISO C++17 does not allow 'register' storage class specifier [-Werror=register]
  286 | register char c, k = 0;