Detect `uname -m` == i686 as a 32-bit host

Change-Id: I0350629ce6ea7a5f0224489bafc98bc190e70932
Test: UNAME from https://groups.google.com/d/msg/android-building/nGQna2xuW5s/eEcXSo9ZBgAJ
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 49ca154..26042fa 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -78,7 +78,7 @@
   HOST_2ND_ARCH := x86
   HOST_IS_64_BIT := true
 else
-ifneq (,$(findstring x86,$(UNAME)))
+ifneq (,$(findstring i686,$(UNAME))$(findstring x86,$(UNAME)))
 $(error Building on a 32-bit x86 host is not supported: $(UNAME)!)
 endif
 endif