rust: add cfg.mk suffix

recipes/rust/rust.inc

@@ -188,8 +188,8 @@ def rust_gen_mk_cfg(d, thing):
 
     p = d.getVar('S', True) + '/mk/cfg/'
 
-    o = open(p + sys_for(d, thing), 'w')
-    i = open(p + rust_base_sys, 'r')
+    o = open(p + sys_for(d, thing) + '.mk', 'w')
+    i = open(p + rust_base_sys + '.mk', 'r')
 
     r = subprocess.call(['sed',
         # update all triplets to the new one

recipes/rust/rust_0.12.0+2014-11-18.bb

@@ -14,4 +14,5 @@ SRC_URI_append = "\
 	file://0027-mk-target-fix-typo-so-we-depend-on-the-correct-direc.patch \
 	file://0028-rustdoc-avoid-supplying-a-bad-default-sysroot-so-the.patch \
 	file://0030-Target-add-default-target.json-path-libdir-rust-targ.patch \
+	file://0031-mk-cfg-add-.mk-suffix-on-files-to-avoid-supprises-wh.patch \
 "