Rework ASSUME_PROVIDED and notes

README.md

@@ -3,6 +3,12 @@
 This openembedded layer provides the rust compiler, tools for building packages
 (cargo), and a few example projects.
 
+By default we assume that there is a local `cargo` (ie: `cargo-native`). To disable this and try to build cargo, add:
+
+    CARGO_PROVIDED = ""
+
+To a conf file (probably local.conf)
+
 ## What works:
 
  - MACHINE="beaglebone" (TARGET_SYS=arm-poky-linux-gnueabi)
@@ -13,12 +19,16 @@ This openembedded layer provides the rust compiler, tools for building packages
 
  - Probably some of the untested things
  - cargo and cargo-native (use a local package for -native)
-	- We provide .bb files for these, and they are working every
-	  now-and-then. Unfortunately, rust moves a bit too quickly for cargo
-          to keep up, and it ends up broken fairly often.
 
-	- To use a local cargo, add `ASSUME_PROVIDED = "cargo-native"` to your
-	  local.conf file (or use the `bitbake -I cargo-native` option)
+### What about cargo?:
+
+We provide .bb files for these, and they are working every now-and-then.
+Unfortunately, rust moves a bit too quickly for cargo to keep up, and it ends
+up broken fairly often.
+
+Very often we'll want newer versions of rust than cargo is able to build with.
+Thankfully, we don't need any custom cargo configuration, and can use a vanilla
+cargo binary.
 
 ## What's untested: