This fixes the following warnings produced by GCC 9:
../tools/lld/MachO/Arch/ARM64.cpp: In member function ‘void {anonymous}::OptimizationHintContext::applyAdrpLdr(const lld::macho::OptimizationHint&)’:
../tools/lld/MachO/Arch/ARM64.cpp:448:18: warning: comparison of integer expressions of different signedness: ‘int64_t’ {aka ‘long int’} and ‘uint64_t’ {aka ‘long unsigned int’} [-Wsign-compare]
448 | if (ldr.offset != (rel1->referentVA & 0xfff))
| ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../tools/lld/MachO/UnwindInfoSection.cpp: In function ‘bool canFoldEncoding(compact_unwind_encoding_t)’:
../tools/lld/MachO/UnwindInfoSection.cpp:404:44: warning: comparison between ‘enum<unnamed>’ and ‘enum<unnamed>’ [-Wenum-compare]
404 | static_assert(UNWIND_X86_64_MODE_MASK == UNWIND_X86_MODE_MASK, "");
| ^~~~~~~~~~~~~~~~~~~~
../tools/lld/MachO/UnwindInfoSection.cpp:405:49: warning: comparison between ‘enum<unnamed>’ and ‘enum<unnamed>’ [-Wenum-compare]
405 | static_assert(UNWIND_X86_64_MODE_STACK_IND == UNWIND_X86_MODE_STACK_IND, "");
| ^~~~~~~~~~~~~~~~~~~~~~~~~
Differential Revision: https://reviews.llvm.org/D130970