Idea: make it easy to add custom steps during the build process

[darealshinji]

I wanted to keep track of installed files and added these 'hooks' to the Makefile:

--- a/Makefile
+++ b/Makefile
@@ -790,6 +790,9 @@ $(PREFIX)/$(3)/installed/$(1): $(PKG_MAKEFILES) \
 	        @echo $(1)~$(3) > '$(PREFIX)/$(3)/lib/$(1).dry-run'
 	        @touch '$(PREFIX)/$(3)/installed/$(1)'
 	    $(else),
+ifdef HOOK_PRE
+	        @$(call HOOK_PRE,$(1),$(3))
+endif
 	        @$(PRINTF_FMT) '[build]'    '$(1)' '$(3)' | $(RTRIM)
 	        @[ -d '$(LOG_DIR)/$(TIMESTAMP)' ] || mkdir -p '$(LOG_DIR)/$(TIMESTAMP)'
 	        @touch '$(LOG_DIR)/$(TIMESTAMP)/$(1)_$(3)'
@@ -812,6 +815,9 @@ $(PREFIX)/$(3)/installed/$(1): $(PKG_MAKEFILES) \
 	        fi
 	        @$(PRINTF_FMT) '[done]' '$(1)' '$(3)' "`grep -a '^du:.*KiB$$\' '$(LOG_DIR)/$(TIMESTAMP)/$(1)_$(3)' | cut -d ':' -f2 | tail -1`" \
 	                                          "`grep -a '^real.*m.*s$$\' '$(LOG_DIR)/$(TIMESTAMP)/$(1)_$(3)' | tr '\t' ' ' | cut -d ' ' -f2 | tail -1`"
+ifdef HOOK_POST
+	        @$(call HOOK_POST,$(1),$(3))
+endif
 	    )
 	$(else),
 	    @$(PRINTF_FMT) '[$(or $($(PKG)_TYPE),disabled)]' '$(1)' '$(3)' | $(RTRIM)

This allows me to easily add my own code through settings.mk:

.NOTPARALLEL:

define HOOK_PRE
	@find '$(PREFIX)' | $(SORT) > '$(MXE_TMP)/tmp-$(1)-$(2).pre'
endef

define HOOK_POST
	@find '$(PREFIX)' | $(SORT) > '$(MXE_TMP)/tmp-$(1)-$(2).post'
	@diff '$(MXE_TMP)/tmp-$(1)-$(2).pre' '$(MXE_TMP)/tmp-$(1)-$(2).post' | grep '^>' > '$(PREFIX)/$(2)/installed/$(1)'
	@rm -f '$(MXE_TMP)/tmp-$(1)-$(2).pre' '$(MXE_TMP)/tmp-$(1)-$(2).post'
endef

Do you think it would be a good idea to add such hooks? I can image someone could also use it for notifications, to backup a config file before the build directory gets deleted, etc.