fix: complete libffi duplicate symbol fix for dynamic builds

This commit completes the fix for duplicate libffi symbol errors that
occur with dynamic builds (DYNAMIC=1). The previous commit only guarded
one of two RTS_LIBFFI_SYMBOLS usages in rts/RtsSymbols.c.

Changes:
1. Guard the second RTS_LIBFFI_SYMBOLS usage at line 1199 with
   #if !defined(INTERNAL_LIBFFI)
2. Update libffi-clib submodule to include -Wno-error in cc-options,
   fixing java_raw_api.c deprecated function warnings treated as errors

When INTERNAL_LIBFFI is defined (default: using libffi-clib package),
the RTS should not register libffi symbols as built-ins since the
libffi-clib package provides them. This prevents GHCi runtime linker
from finding duplicate definitions when loading libffi-clib.

Author: angerman

libraries/libffi-clib

@@ -1196,7 +1196,9 @@ RtsSymbolVal rtsSyms[] = {
       RTS_LIBGCC_SYMBOLS
       RTS_ARCH_LIBGCC_SYMBOLS
       RTS_FINI_ARRAY_SYMBOLS
+#if !defined(INTERNAL_LIBFFI)
       RTS_LIBFFI_SYMBOLS
+#endif
       RTS_ARM_OUTLINE_ATOMIC_SYMBOLS
       RTS_SYMBOLS_PRIM
       SymI_HasDataProto(nonmoving_write_barrier_enabled)