Try to fix lmdbxx download

.gitlab-ci.yml

@@ -4,7 +4,7 @@ variables:
   # prevent configure tzdata hanging apt install commands
   DEBIAN_FRONTEND: noninteractive
 
-build-gcc7:
+build-gcc9:
   stage: build
   image: ubuntu:20.04
   tags: [docker]

CMakeLists.txt

@@ -487,10 +487,10 @@ if(USE_BUNDLED_LMDBXX)
 		lmdbxx
 		URL "https://raw.githubusercontent.com/hoytech/lmdbxx/1.0.0/lmdb++.h"
 		DOWNLOAD_NO_EXTRACT TRUE
+		CONFIGURE_COMMAND ""
+		BUILD_COMMAND ""
 		)
-	if(NOT lmdbxx_POPULATED)
-		FetchContent_Populate(lmdbxx)
-	endif()
+	FetchContent_Populate(lmdbxx)
 	add_library(lmdbxx INTERFACE)
 	target_include_directories(lmdbxx INTERFACE ${lmdbxx_SOURCE_DIR})
 	add_library(lmdbxx::lmdbxx ALIAS lmdbxx)