Fix for "ld.lld: error: undefined symbol: _Uaarch64_setcontext" when doing build for FreeBSD-arm64 using internal libunwind (#110432)

* Fix for "ld.lld: error: undefined symbol: _Uaarch64_setcontext" when doing build for arm64 using internal libunwind

* New lines

* 'comment'

* stick to naming

Author: sec

src/native/external/libunwind.cmake

@@ -97,6 +97,7 @@ elseif(CLR_CMAKE_TARGET_FREEBSD)
     set(libunwind_la_SOURCES_arm_os_local       arm/Los-freebsd.c)
     set(libunwind_la_SOURCES_aarch64_os         aarch64/Gos-freebsd.c)
     set(libunwind_la_SOURCES_aarch64_os_local   aarch64/Los-freebsd.c)
+    set(libunwind_aarch64_la_SOURCES_os         aarch64/setcontext.S)
     list(APPEND libunwind_coredump_la_SOURCES   coredump/_UCD_access_reg_freebsd.c)
 elseif(CLR_CMAKE_HOST_SUNOS)
     set(libunwind_la_SOURCES_os                 ${libunwind_la_SOURCES_os_solaris})
@@ -229,7 +230,7 @@ set(libunwind_la_SOURCES_aarch64_common
 # The list of files that go into libunwind:
 set(libunwind_la_SOURCES_aarch64
     ${libunwind_la_SOURCES_aarch64_common}
-    ${libunwind_la_SOURCES_aarch64_os_local}
+    ${libunwind_la_SOURCES_aarch64_os_local} ${libunwind_aarch64_la_SOURCES_os}
     ${libunwind_la_SOURCES_local}
     aarch64/Lapply_reg_state.c aarch64/Lreg_states_iterate.c
     aarch64/Lcreate_addr_space.c aarch64/Lget_proc_info.c