restructured build system support

cmake/PreProjectConfig.cmake

@@ -0,0 +1,63 @@
+function(pre_project_config)
+
+# Basic input sanitization
+if(DEFINED TGT_BSP)
+	if(${TGT_BSP} MATCHES "arm/raspberrypi" AND NOT ${OS_FSFW} MATCHES linux)
+		message(STATUS "FSFW OSAL invalid for specified target BSP ${TGT_BSP}!")
+		message(STATUS "Setting valid OS_FSFW: linux") 
+		set(OS_FSFW "linux")
+	endif()
+endif()
+
+# Disable compiler checks for cross-compiling.
+if(${OS_FSFW} STREQUAL linux AND TGT_BSP)
+
+	if(${TGT_BSP} MATCHES "arm/q7s")
+		set(CMAKE_TOOLCHAIN_FILE 
+			"${CMAKE_SCRIPT_PATH}/Q7SCrossCompileConfig.cmake"
+			PARENT_SCOPE
+		)
+	elseif (${TGT_BSP} MATCHES "arm/raspberrypi")
+		if(NOT DEFINED ENV{RASPBIAN_ROOTFS})
+			if(NOT RASPBIAN_ROOTFS)
+				set(ENV{RASPBIAN_ROOTFS} "$ENV{HOME}/raspberrypi/rootfs")
+			else()
+				set(ENV{RASPBIAN_ROOTFS} "${RASPBIAN_ROOTFS}")
+			endif()
+		else()	
+			message(STATUS 
+				"RASPBIAN_ROOTFS from environmental variables used: "
+				"$ENV{RASPBIAN_ROOTFS}"
+			)
+		endif()
+	
+		if(NOT DEFINED ENV{RASPBERRY_VERSION})
+			if(NOT RASPBERRY_VERSION)
+				message(STATUS "No RASPBERRY_VERSION specified, setting to 4")
+				set(RASPBERRY_VERSION "4" CACHE STRING "Raspberry Pi version")
+			else()
+				message(STATUS 
+					"Setting RASPBERRY_VERSION to ${RASPBERRY_VERSION}"
+				)
+				set(RASPBERRY_VERSION 
+					${RASPBERRY_VERSION} CACHE STRING "Raspberry Pi version"
+				)
+			set(ENV{RASPBERRY_VERSION} ${RASPBERRY_VERSION})
+			endif()
+		else()
+			message(STATUS 
+				"RASPBERRY_VERSION from environmental variables used: "
+				"$ENV{RASPBERRY_VERSION}"
+			)
+		endif()
+
+		set(CMAKE_TOOLCHAIN_FILE 
+			"${CMAKE_SCRIPT_PATH}/RPiCrossCompileConfig.cmake"
+			PARENT_SCOPE
+		)
+	else()
+		message(WARNING "Target BSP (TGT_BSP) ${TGT_BSP} unknown!")
+	endif()
+endif()
+
+endfunction()