fixup! deps: update libffi to 3.6.0

Author: aduh95

deps/libffi/libffi.gyp

@@ -118,7 +118,7 @@
         ['target_arch == "ppc64" and OS == "aix"', {
           'variables': {
             'libffi_arch_sources': [
-              'src/powerpc/ffi_darwin.c',
+              'src/powerpc/ffi.c',
               'src/powerpc/aix.S',
               'src/powerpc/aix_closure.S',
             ],