Set kernel gcc version to 4.8 for ARM targets

* This causes the check during path setup for an arm-eabi-4.9 toolchain to fail,
      thus only leaving the arm-linux-androideabi- to exist.
* This is only temporary as Google is building with 4.9 and 4.8 gcc's
       have been removed in their next release

Was updated to 4.9 here: CyanogenMod/android_build@bf8346e
Toolchain check here: https://github.com/CyanogenMod/android_build/blob/cm-13.0/envsetup.sh#L189

Change-Id: I24bff10e392a6cdced1797870e523144e83d611d
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>

core/combo/TARGET_linux-arm.mk

@@ -38,6 +38,7 @@ $(combo_2nd_arch_prefix)TARGET_NDK_GCC_VERSION := 4.9
 
 ifeq ($(strip $(TARGET_GCC_VERSION_EXP)),)
 $(combo_2nd_arch_prefix)TARGET_GCC_VERSION := 4.9
+$(combo_2nd_arch_prefix)TARGET_LEGACY_GCC_VERSION := 4.8
 else
 $(combo_2nd_arch_prefix)TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
 endif

envsetup.sh

@@ -190,6 +190,7 @@ function setpaths()
     # defined in core/config.mk
     targetgccversion=$(get_build_var TARGET_GCC_VERSION)
     targetgccversion2=$(get_build_var 2ND_TARGET_GCC_VERSION)
+    targetlegacygccversion=$(get_build_var TARGET_LEGACY_GCC_VERSION)
     export TARGET_GCC_VERSION=$targetgccversion
 
     # The gcc toolchain does not exists for windows/cygwin. In this case, do not reference it.
@@ -225,7 +226,7 @@ function setpaths()
     case $ARCH in
         arm)
             # Legacy toolchain configuration used for ARM kernel compilation
-            toolchaindir=arm/arm-eabi-$targetgccversion/bin
+            toolchaindir=arm/arm-eabi-$targetlegacygccversion/bin
             if [ -d "$gccprebuiltdir/$toolchaindir" ]; then
                  export ARM_EABI_TOOLCHAIN="$gccprebuiltdir/$toolchaindir"
                  ANDROID_KERNEL_TOOLCHAIN_PATH="$ARM_EABI_TOOLCHAIN":