[build] improve build version stuff

- always save build version when updating anything that depends on libpprz, so it will also be updated on e.g. make tmtc
- only warn if the version number (major.minor.patch) is different, disregard the label, sha1, dirty postfixes in the string...

Makefile

@@ -108,6 +108,8 @@ print_build_version:
 	@echo "------------------------------------------------------------"
 	@echo "Building Paparazzi version" $(shell ./paparazzi_version)
 	@echo "------------------------------------------------------------"
+
+save_build_version:
 	$(Q)test -d $(PAPARAZZI_HOME)/var || mkdir -p $(PAPARAZZI_HOME)/var
 	$(Q)./paparazzi_version > $(PAPARAZZI_HOME)/var/build_version.txt
 
@@ -125,7 +127,7 @@ ground_segment.opt: ground_segment cockpit.opt tmtc.opt
 
 static: cockpit tmtc generators sim_static joystick static_h
 
-libpprz:
+libpprz: save_build_version
 	$(MAKE) -C $(LIB)/ocaml
 
 multimon:
@@ -311,7 +313,7 @@ run_tests:
 test: all replace_current_conf_xml run_tests restore_conf_xml
 
 
-.PHONY: all print_build_version update_google_version dox ground_segment ground_segment.opt \
+.PHONY: all print_build_version save_build_version update_google_version dox ground_segment ground_segment.opt \
 subdirs $(SUBDIRS) conf ext libpprz multimon cockpit cockpit.opt tmtc tmtc.opt generators\
 static sim_static lpctools commands \
 clean cleanspaces ab_clean dist_clean distclean dist_clean_irreversible \

Makefile.ac

@@ -84,7 +84,7 @@ ifneq ($(words $(GIT_SHA1)),1)
 GIT_SHA1 := "UNKNOWN"
 endif
 GIT_DESC := $(shell ./paparazzi_version)
-BUILD_DESC := $(shell cat $(PAPARAZZI_HOME)/var/build_version.txt)
+BUILD_DESC := $(shell cat $(PAPARAZZI_HOME)/var/build_version.txt 2> /dev/null || echo UNKNOWN)
 PPRZ_VER := $(shell echo $(GIT_DESC) | sed 's/[^0-9.]*\([0-9.]*\).*/\1/')
 PPRZ_VER_MAJOR := $(shell echo $(GIT_DESC) | sed 's/v\([0-9]*\).*/\1/')
 PPRZ_VER_MINOR := $(shell echo $(GIT_DESC) | sed 's/v[0-9]*.\([0-9]*\).*/\1/')
@@ -99,11 +99,12 @@ export PPRZ_VER_MAJOR
 export PPRZ_VER_MINOR
 export PPRZ_VER_PATCH
 
-ifneq ($(GIT_DESC),$(BUILD_DESC))
-VERSION_MATCH = "\nWarning: version differ from build version ($(BUILD_DESC))"
-else
 VERSION_MATCH = ""
+#ifneq ($(BUILD_DESC), UNKNOWN)
+ifeq (,$(findstring $(PPRZ_VER),$(BUILD_DESC)))
+VERSION_MATCH = "\nWarning: version differs from build version ($(BUILD_DESC)), you might want to run the toplevel make."
 endif
+#endif
 
 # "make Q=''" to get full echo
 Q=@