Split main Kconfig to allow application specific Kconfig

This will allow adding an application level Kconfig, for example

	mainmenu "Zephyr Application"

	config ZEPHYR_BASE
	    string
	    option env="ZEPHYR_BASE"

	config APPLICATION_BASE
	    string
	    option env="PROJECT_BASE"

	source "$ZEPHYR_BASE/Kconfig.zephyr"

	config TESTME
		bool "Test me"
		default y

	config BLAH
		bool "blah"
		default y

	source "$APPLICATION_BASE/src/Kconfig"

In the application file, add the following for example:

KBUILD_KCONFIG := $(PWD)/Kconfig
export KBUILD_KCONFIG

Change-Id: I7b7a6daace5f589ddadab0f0de54b5adc1b8dc86
Signed-off-by: Anas Nashif <anas.nashif@intel.com>

Kconfig

@@ -31,24 +31,4 @@
 #
 mainmenu "Zephyr Kernel/$SRCARCH Configuration"
 
-
-config SRCARCH
-        string
-        option env="SRCARCH"
-
-source "arch/$SRCARCH/Kconfig"
-
-
-config ARCH
-        string
-        option env="ARCH"
-
-config KERNELVERSION
-        string
-        option env="KERNELVERSION"
-
-config DEFCONFIG_LIST
-        string
-        option defconfig_list
-        default "$ARCH_DEFCONFIG"
-        default "arch/$ARCH/defconfig"
+source "Kconfig.zephyr"

Kconfig.zephyr

@@ -0,0 +1,52 @@
+# Kconfig - general configuration options
+
+#
+# Copyright (c) 2014-2015 Wind River Systems, Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1) Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2) Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3) Neither the name of Wind River Systems nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+config SRCARCH
+        string
+        option env="SRCARCH"
+
+source "arch/$SRCARCH/Kconfig"
+
+
+config ARCH
+        string
+        option env="ARCH"
+
+config KERNELVERSION
+        string
+        option env="KERNELVERSION"
+
+config DEFCONFIG_LIST
+        string
+        option defconfig_list
+        default "$ARCH_DEFCONFIG"
+        default "arch/$ARCH/defconfig"