common_src_dirs   = $(PROJECT_DIR)/src/*/
common_src_files  = $(addsuffix *.c,$(common_src_dirs))
common_sort_files = $(sort $(wildcard $(common_src_files)))
COMMON_SRCS       = $(subst $(PROJECT_DIR)/src/,src/,$(common_sort_files))

app_src_dirs      = $(PROJECT_DIR)/src/
app_src_files     = $(addsuffix *.c,$(app_src_dirs))
app_sort_files    = $(sort $(wildcard $(app_src_files)))
APP_SRCS          = $(subst $(PROJECT_DIR)/src/,src/,$(app_sort_files))