[PATCH] BaseTools:Fixed build failure when specifying multiple BUILDTARGET

["Fan, ZhijuX" <zhijux.fan@intel.com>]

With Python3, the dict.value() method returns an iterator.
If a dictionary is updated while an iterator on its keys is used,
a RuntimeError is generated.
Converting the iterator to a list() forces a copy of the mutable
keys in an immutable list which can be safely iterated.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
---
 BaseTools/Source/Python/AutoGen/AutoGen.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/BaseTools/Source/Python/AutoGen/AutoGen.py b/BaseTools/Source/Python/AutoGen/AutoGen.py
index 2452ecbcba..7969e46d87 100644
--- a/BaseTools/Source/Python/AutoGen/AutoGen.py
+++ b/BaseTools/Source/Python/AutoGen/AutoGen.py
@@ -580,7 +580,7 @@ class WorkspaceAutoGen(AutoGen):
                                 if NewPcd2 not in GlobalData.MixedPcd[item]:
                                     GlobalData.MixedPcd[item].append(NewPcd2)
 
-            for BuildData in PGen.BuildDatabase._CACHE_.values():
+            for BuildData in list(PGen.BuildDatabase._CACHE_.values()):
                 if BuildData.Arch != Arch:
                     continue
                 for key in BuildData.Pcds:
-- 
2.14.1.windows.1