The wrapper features.h gets pulled in by system headers causing thigns to
break. We work around it by simply not wrap features.h

--- ./config/system-headers.mozbuild.orig
+++ ./config/system-headers.mozbuild
@@ -229,7 +229,6 @@
     'execinfo.h',
     'extras.h',
     'fcntl.h',
-    'features.h',
     'fenv.h',
     'ffi.h',
     'fibdef.h',
