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

diff --git a/config/system-headers.mozbuild b/config/system-headers.mozbuild
index 07d48e7..d2ce2b2 100644
--- a/config/system-headers.mozbuild
+++ b/config/system-headers.mozbuild
@@ -227,3 +227,2 @@ system_headers = [
     "fcntl.h",
-    "features.h",
     "fenv.h",