Switch default gcc toolchain from 4.4.3 to 4.6.

Switch both arm-linux-androideabi toolchainand arm-eabi toolchain.

Change-Id: I7b2771fe684853ab37e3b5b7cfe4146f9f901e02
diff --git a/envsetup.sh b/envsetup.sh
index b7ca7d2..7711e0d 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -112,18 +112,19 @@
     # and in with the new
     CODE_REVIEWS=
     prebuiltdir=$(getprebuilt)
+    gccprebuiltdir=$(get_abs_build_var ANDROID_GCC_PREBUILTS)
 
     # The gcc toolchain does not exists for windows/cygwin. In this case, do not reference it.
     export ANDROID_EABI_TOOLCHAIN=
-    toolchaindir=toolchain/arm-linux-androideabi-4.4.x/bin
-    if [ -d "$prebuiltdir/$toolchaindir" ]; then
-        export ANDROID_EABI_TOOLCHAIN=$prebuiltdir/$toolchaindir
+    toolchaindir=arm/arm-linux-androideabi-4.6/bin
+    if [ -d "$gccprebuiltdir/$toolchaindir" ]; then
+        export ANDROID_EABI_TOOLCHAIN=$gccprebuiltdir/$toolchaindir
     fi
 
     export ARM_EABI_TOOLCHAIN=
-    toolchaindir=toolchain/arm-eabi-4.4.3/bin
-    if [ -d "$prebuiltdir/$toolchaindir" ]; then
-        export ARM_EABI_TOOLCHAIN=$prebuiltdir/$toolchaindir
+    toolchaindir=arm/arm-eabi-4.6/bin
+    if [ -d "$gccprebuiltdir/$toolchaindir" ]; then
+        export ARM_EABI_TOOLCHAIN=$gccprebuiltdir/$toolchaindir
     fi
 
     export ANDROID_TOOLCHAIN=$ANDROID_EABI_TOOLCHAIN