diff --git a/build/osx/wxcarbon.xcconfig b/build/osx/wxcarbon.xcconfig
index 398e6733a6..3160bd64e3 100644
--- a/build/osx/wxcarbon.xcconfig
+++ b/build/osx/wxcarbon.xcconfig
@@ -9,6 +9,7 @@ SDKROOT = macosx10.7
 GCC_VERSION[arch=ppc] = 4.0
 
 ARCHS = ppc i386
+VALID_ARCHS = ppc i386
 
 OTHER_LDFLAGS = -framework WebKit -framework IOKit -framework Carbon -framework Cocoa -framework AudioToolbox -framework AGL -framework OpenGL -framework QuickTime