Workaround more '#error' cppcheck error messages

Workaround more '#error' cppcheck error messages

* darwin_stop_world.c (GC_stack_range_for): Skip #error pragma if
CPPCHECK.
* dyn_load.c [DYNAMIC_LOADING && !PCR && !DARWIN]: Likewise.
* dyn_load.c [SOLARISDL && !PCR && !GC_SOLARIS_THREADS && THREADS]:
Likewise.
* include/private/gc_priv.h [!POWERPC && !I386 && !X86_64 && !ARM32
&& !AARCH64] (GC_THREAD_STATE_T): Likewise.
* include/private/gcconfig.h [GC_IRIX_THREADS && !IRIX5 || ...]:
Likewise.
* include/private/gcconfig.h [PARALLEL_MARK && !THREADS]: Likewise.
* include/private/gcconfig.h [MARK_BIT_PER_GRANULE && MARK_BIT_PER_OBJ
|| ...]: Likewise.
* pcr_interface.c [PCR] (GC_enumerate_block): Likewise.
* win32_threads.c [!I386 && !X86_64 && !ARM32 && !SHx && !MIPS && !PPC
&& !ALPHA] (GC_push_stack_for): Likewise.
* darwin_stop_world.c (GC_stack_range_for): Initialize "lo" local
variable even if platform unsupported.