Fix #438: Set OSAL_SYSTEM_BSPTYPE for native builds

This explicitly specifies the BSP to use when using SIMULATION=native
flags to the build.  All other example toolchain files already included
this setting.

cmake/arch_build.cmake

@@ -280,6 +280,7 @@ function(prepare)
             "${CMAKE_SYSTEM_NAME}" STREQUAL "CYGWIN")
       # Export the variables determined here up to the parent scope
       SET(CFE_SYSTEM_PSPNAME      "pc-linux" PARENT_SCOPE)
+      SET(OSAL_SYSTEM_BSPTYPE     "pc-linux" PARENT_SCOPE)
       SET(OSAL_SYSTEM_OSTYPE      "posix"    PARENT_SCOPE)
     else ()
       # Not cross compiling and host system is not recognized