xtools: get rid of warnings about wrong path

Eliminate following errors:

make[2]: /home/nashif/Work/sdk/xtools/outdir/x-tools//bin/-gcc: Command
not found
make[2]: /home/nashif/Work/sdk/xtools/outdir/x-tools//bin/-gcc: Command
not found
make[2]: /home/nashif/Work/sdk/xtools/outdir/x-tools//bin/-gcc: Command
not found

Also, usage of CROSS_COMPILE with a predefined toolchain is not required and
complicates things, just call CROSS_COMPILE with the full path if you
want to build with a toolchain not supported with Zephyr.

Change-Id: I93ec4ff2e04d22cee82c8e4b74b652927572b30a
Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/Makefile.toolchain.xtools

@@ -1,27 +1,32 @@
 ifndef XTOOLS_TOOLCHAIN_PATH
-
-ifeq ($(CROSS_COMPILE),)
 $(error XTOOLS_TOOLCHAIN_PATH is not set)
-else
-CROSS_COMPILE_TARGET = $(patsubst %-,%,${CROSS_COMPILE})
-CROSS_COMPILE_ROOT = $(dir $(shell which ${CROSS_COMPILE}gcc))/..
 endif
 
-else
+ifndef MAKEFILE_TOOLCHAIN_DO_PASS2
 
+# arm
 CROSS_COMPILE_TARGET_arm = arm-none-eabi
-CROSS_COMPILE_TARGET_x86 = i586-pc-elf
+
+# x86
+CROSS_COMPILE_TARGET_x86 = i586-unknown-elf
 
 CROSS_COMPILE_TARGET = ${CROSS_COMPILE_TARGET_${ARCH}}
 CROSS_COMPILE_ROOT = ${XTOOLS_TOOLCHAIN_PATH}/${CROSS_COMPILE_TARGET}
-CROSS_COMPILE = ${CROSS_COMPILE_ROOT}/bin/${CROSS_COMPILE_TARGET}-
 
-endif
+else
+
+CROSS_COMPILE = ${CROSS_COMPILE_ROOT}/bin/${CROSS_COMPILE_TARGET}-
 
 TOOLCHAIN_CFLAGS = -I${CROSS_COMPILE_ROOT}/${CROSS_COMPILE_TARGET}/sysroot/usr/include
 TOOLCHAIN_LIBS = gcc
 
 CROSS_COMPILE_version = $(shell $(CROSS_COMPILE)gcc -dumpversion)
 LIB_INCLUDE_DIR += -L ${CROSS_COMPILE_ROOT}/lib/gcc/${CROSS_COMPILE_TARGET}/${CROSS_COMPILE_version}/
 
+endif
+
 export CROSS_COMPILE TOOLCHAIN_LIBS LIB_INCLUDE_DIR TOOLCHAIN_CFLAGS
+
+ifndef MAKEFILE_TOOLCHAIN_DO_PASS2
+MAKEFILE_TOOLCHAIN_DO_PASS2=true
+endif