make: use `shell` command to extract version string
@@ -329,7 +329,7 @@ endif
ifeq ("$(wildcard ${IDF_PATH}/version.txt)","")
IDF_VER_T := $(shell cd ${IDF_PATH} && git describe --always --tags --dirty)
else
-IDF_VER_T := `cat ${IDF_PATH}/version.txt`
+IDF_VER_T := $(shell cat ${IDF_PATH}/version.txt)
endif
IDF_VER := $(shell echo "$(IDF_VER_T)" | cut -c 1-31)
