Allow INSTALL_LIB_DIR and friends to be able to be

set form outside

Change-Id: Id637174dc724dbabc7f4b265ea908bedc4e7153e

Author: silvakid

install_layout.cmake

@@ -107,15 +107,23 @@ endif()
 # These variables should be used in install specs.
 #
 
-set(INSTALL_LIB_DIR ${CMAKE_INSTALL_LIBDIR})
+if(NOT INSTALL_LIB_DIR)
+  set(INSTALL_LIB_DIR ${CMAKE_INSTALL_LIBDIR})
+endif()
 
-set(INSTALL_LIB_DIR_STATIC "${INSTALL_LIB_DIR}")
-if(VS)
-  set(INSTALL_LIB_DIR_STATIC "${INSTALL_LIB_DIR_STATIC}/${VS}")
+if(NOT INSTALL_LIB_DIR_STATIC)
+  set(INSTALL_LIB_DIR_STATIC "${INSTALL_LIB_DIR}")
+  if(VS)
+    set(INSTALL_LIB_DIR_STATIC "${INSTALL_LIB_DIR_STATIC}/${VS}")
+  endif()
 endif()
 
-set(INSTALL_INCLUDE_DIR ${CMAKE_INSTALL_INCLUDEDIR})
-set(INSTALL_DOC_DIR ${CMAKE_INSTALL_DOCDIR})
+if(NOT INSTALL_INCLUDE_DIR)
+  set(INSTALL_INCLUDE_DIR ${CMAKE_INSTALL_INCLUDEDIR})
+endif()
+if(NOT INSTALL_DOC_DIR)
+  set(INSTALL_DOC_DIR ${CMAKE_INSTALL_DOCDIR})
+endif()
 
 #
 # Store layout settings in the cache.