mdbx: disable unused check

Makefile

@@ -19,6 +19,7 @@ DOCKER_TAG ?= thorax/erigon:latest
 CGO_CFLAGS := $(shell $(GO) env CGO_CFLAGS 2>/dev/null) # don't lose default
 CGO_CFLAGS += -DMDBX_FORCE_ASSERTIONS=0 # Enable MDBX's asserts by default in 'devel' branch and disable in releases
 CGO_CFLAGS += -DMDBX_DISABLE_VALIDATION=1 # This feature is not ready yet
+CGO_CFLAGS += -DMDBX_ENV_CHECKPID=0 # Erigon doesn't do fork() syscall
 CGO_CFLAGS += -O
 CGO_CFLAGS += -D__BLST_PORTABLE__
 CGO_CFLAGS += -Wno-error=strict-prototypes # for Clang15, remove it when can https://github.com/ledgerwatch/erigon/issues/6113#issuecomment-1359526277