contrib/lmdb: avoid -Wshadow with embedded lmdb

Unfortunately, CFLAGS are concatenated in the other order than we would
need for this, so let's choose this approach.
31 jobs for <span class="ref-name">lmdb-nowarn</span> in 6 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
canceled #218749
docker linux amd64
build:asan:linux:amd64

00:00:06

canceled #218748
docker linux amd64
build:linux:amd64

00:00:06

canceled #218750
docker linux amd64 allowed to fail
srpm

00:00:05

 
  Test
canceled #218759
docker linux amd64
deckard:linux:amd64

canceled #218767
privileged
distro:epel-7

canceled #218766
privileged
distro:fedora-29

canceled #218758
docker
doc

canceled #218756
dind
docker:build

canceled #218757
docker linux amd64
installcheck:linux:amd64

canceled #218760
docker linux amd64
installcheck:valgrind:linux:amd64

canceled #218753
docker
lint:c

canceled #218754
docker
lint:clang-scan-build

canceled #218752
docker
lint:lua

canceled #218751
docker linux amd64
lint:pedantic

canceled #218761
docker
osx:build

canceled #218763
docker linux amd64
pytests:lint

canceled #218764
docker linux amd64
pytests:run

canceled #218765
docker linux amd64
respdiff:iter:udp:linux:amd64

canceled #218755
docker linux amd64
test:linux:amd64

canceled #218762
docker linux amd64
test:linux:amd64:valgrind

 
  Extended
canceled #218768
docker linux amd64
pytests:extended

canceled #218769
respdiff
respdiff:fwd-tls6-kresd.udp6

canceled #218770
respdiff
respdiff:fwd-udp6-kresd.udp6

canceled #218774
respdiff
respdiff:fwd-udp6-unbound.tcp6

canceled #218775
respdiff
respdiff:fwd-udp6-unbound.tls6

canceled #218773
respdiff
respdiff:fwd-udp6-unbound.udp6

canceled #218772
respdiff
respdiff:iter.tls6

canceled #218771
respdiff
respdiff:iter.udp6

canceled #218776
respdiff
resperf:fwd-tls6.udp-asan

canceled #218777
respdiff
resperf:fwd-udp6.udp-asan

canceled #218778
respdiff
resperf:iter.udp-asan