Makefile: document configure cache handling

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

diff --git a/Makefile b/Makefile
index f8303e137636a5683e17c0856dae72d8644b4e88..bf04773d26ed451776c9d118bb0784f86a1bde0c 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -441,6 +441,7 @@ external-deps:
                SPIDER=--spider source
 
 ifeq ($(BR2_CONFIG_CACHE),y)
+# drop configure cache if configuration is changed
 $(BUILD_DIR)/tgt-config.cache: .config
        rm -f $@
        touch $@