[ARM] Extend the usage of TARGET_GCC_VERSION for gdb and arm-eabi-*.

In the future to upgrade the gcc version we just need to edit one
line in core/config.mk.

Change-Id: I01bb38c38f2388913bb7369aa4b2da480411dfbe
diff --git a/envsetup.sh b/envsetup.sh
index c758fcc..1b70d10 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -116,13 +116,16 @@
     prebuiltdir=$(getprebuilt)
     gccprebuiltdir=$(get_abs_build_var ANDROID_GCC_PREBUILTS)
 
+    # defined in core/config.mk
+    targetgccversion=$(get_build_var TARGET_GCC_VERSION)
+
     # The gcc toolchain does not exists for windows/cygwin. In this case, do not reference it.
     export ANDROID_EABI_TOOLCHAIN=
     local ARCH=$(get_build_var TARGET_ARCH)
     case $ARCH in
         x86) toolchaindir=x86/i686-linux-android-4.6/bin
             ;;
-        arm) toolchaindir=arm/arm-linux-androideabi-4.6/bin
+        arm) toolchaindir=arm/arm-linux-androideabi-$targetgccversion/bin
             ;;
         mips) toolchaindir=mips/mipsel-linux-android-4.6/bin
             ;;
@@ -138,7 +141,7 @@
     unset ARM_EABI_TOOLCHAIN ARM_EABI_TOOLCHAIN_PATH
     case $ARCH in
         arm)
-            toolchaindir=arm/arm-eabi-4.6/bin
+            toolchaindir=arm/arm-eabi-$targetgccversion/bin
             if [ -d "$gccprebuiltdir/$toolchaindir" ]; then
                  export ARM_EABI_TOOLCHAIN="$gccprebuiltdir/$toolchaindir"
                  ARM_EABI_TOOLCHAIN_PATH=":$gccprebuiltdir/$toolchaindir"