Readability, and don't -I embedded lmdb if not using it.
# Flags
BUILD_LDFLAGS += $(LDFLAGS)
-BUILD_CFLAGS := $(CFLAGS) -std=c99 -D_GNU_SOURCE -Wno-unused -Wtype-limits -Wformat -Wformat-security -Wall -I$(abspath .) -I$(abspath lib/generic) -I$(abspath contrib) -I$(abspath contrib/lmdb)
+BUILD_CFLAGS := $(CFLAGS) -std=c99 -D_GNU_SOURCE
+BUILD_CFLAGS += -Wno-unused -Wtype-limits -Wformat -Wformat-security -Wall
+BUILD_CFLAGS += -I$(abspath .) -I$(abspath lib/generic) -I$(abspath contrib)
BUILD_CFLAGS += -DPACKAGE_VERSION="\"$(VERSION)\"" -DPREFIX="\"$(PREFIX)\"" -DMODULEDIR="\"$(MODULEDIR)\""
BUILD_CFLAGS += -fvisibility=hidden
ifeq (,$(findstring -O,$(CFLAGS)))
contrib/lmdb/midl.c
contrib_CFLAGS += -pthread
contrib_LIBS += -pthread
+lmdb_CFLAGS += -I$(abspath contrib/lmdb)
endif
$(eval $(call make_static,contrib,contrib))