renamed variable, removed uppercase config text

Config.in

@@ -239,8 +239,8 @@ config BR2_HAVE_INFOPAGES
 	  If you say n here, your target will not contain any
 	  infopage.
 
-config BR2_TARGET_DEV_FILES
-	bool "Development files in target filesystem"
+config BR2_HAVE_DEVFILES
+	bool "development files in target filesystem"
 	default n
 	help
 	  Install headers and static libraries in the

Makefile

@@ -318,7 +318,7 @@ erase-fakeroots:
 	rm -f $(PROJECT_BUILD_DIR)/.fakeroot*
 
 target-devfiles:
-ifeq ($(strip $(BR2_TARGET_DEV_FILES)),y)
+ifeq ($(strip $(BR2_HAVE_DEVFILES)),y)
 	cp -a $(STAGING_DIR)/usr/include $(TARGET_DIR)/usr
 	cp $(STAGING_DIR)/usr/lib/*.a $(TARGET_DIR)/usr/lib
 	cp $(STAGING_DIR)/lib/*.a $(TARGET_DIR)/lib