MC: Tweak variable assignment diagnostics, and make reassignment of non-absolute
variables and symbols invalid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84232 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 1a6e8b6..0e44ee1 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -125,6 +125,7 @@
   OS << '\n';
 
   // FIXME: Lift context changes into super class.
+  // FIXME: Set associated section.
   Symbol->setValue(Value);
 }