Build fails under pypy(3) when enabling these flags.

--- llfuse-1.3/setup.py
+++ llfuse-1.3/setup.py
@@ -84,12 +84,12 @@
     compile_args.append('-Wno-unused-parameter')
 
     # Value-changing conversions should always be explicit.
-    compile_args.append('-Werror=conversion')
+    # compile_args.append('-Werror=conversion')
 
     # Note that (i > -1) is false if i is unsigned (-1 will be converted to
     # a large positive value). We certainly don't want to do this by
     # accident.
-    compile_args.append('-Werror=sign-compare')
+    # compile_args.append('-Werror=sign-compare')
 
     # Enable all fatal warnings only when compiling from Mercurial tip.
     # (otherwise we break forward compatibility because compilation with newer