cmake: Cleanups to work with Windows

tools/cmake/idf_functions.cmake

@@ -18,8 +18,7 @@ macro(idf_set_global_variables)
     # (cmake calls this CMAKE_SOURCE_DIR, keeping old name for compatibility.)
     set(PROJECT_PATH "${CMAKE_SOURCE_DIR}")
 
-    # Note: "main" is no longer a component...
-    #
+    # Note: Unlike older build system, "main" is no longer a component. See build docs for details.    
     set_default(COMPONENT_DIRS "${PROJECT_PATH}/components ${EXTRA_COMPONENT_DIRS} ${IDF_PATH}/components")
     spaces2list(COMPONENT_DIRS)
 

tools/cmake/project.cmake

@@ -7,9 +7,10 @@ set(IDF_PATH "$ENV{IDF_PATH}")
 if(NOT IDF_PATH)
     # Documentation says you should set IDF_PATH in your environment, but we
     # can infer it here if it's not set.
-    set(IDF_PATH ${CMAKE_CURRENT_LIST_DIR})
-    set($ENV{IDF_PATH} "${IDF_PATH}")
+    set(IDF_PATH ${CMAKE_CURRENT_LIST_DIR})    
 endif()
+file(TO_CMAKE_PATH "${IDF_PATH}" IDF_PATH)
+set($ENV{IDF_PATH} "${IDF_PATH}")
 
 #
 # Load cmake modules