lib/oe/classextend: Ensure we don't extend expressions more than once

We could end up with MLPREFIX being prepended to variables like
PACKAGE_DYNAMIC. This patch avoids the problem and unbreaks builds.

[YOCTO #3389]

(From OE-Core rev: 18b401f4f8e931dca08a2e9be34e94c49b5215b9)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/meta/lib/oe/classextend.py b/meta/lib/oe/classextend.py
index 857a6c97ef..fe9b566e7c 100644
--- a/meta/lib/oe/classextend.py
+++ b/meta/lib/oe/classextend.py
@@ -40,7 +40,9 @@ class ClassExtender(object):
         var = var.split()
         newvar = []
         for v in var:
-            if v.startswith("^"):
+            if v.startswith("^" + self.extname):
+                newvar.append(v)
+            elif v.startswith("^"):
                 newvar.append("^" + self.extname + "-" + v[1:])
             else:
                 newvar.append(self.extend_name(v))