db_mongodb: Adopt cmake for mongoc2

src/modules/db_mongodb/CMakeLists.txt

@@ -5,7 +5,17 @@ add_library(${module_name} SHARED ${MODULE_SOURCES})
 # libmongoc-1.0 is required for this module Missing dependency on Ubuntu 20.04
 # of libzstd-dev find_package(zstd REQUIRED)
 find_package(PkgConfig REQUIRED)
-pkg_check_modules(mongoc REQUIRED IMPORTED_TARGET libmongoc-1.0>=1.7)
-add_library(mongoc::mongoc ALIAS PkgConfig::mongoc)
+pkg_check_modules(mongoc2 IMPORTED_TARGET mongoc2)
+
+if(mongoc2_FOUND)
+  add_library(mongoc::mongoc ALIAS PkgConfig::mongoc2)
+else()
+  pkg_check_modules(mongoc IMPORTED_TARGET libmongoc-1.0>=1.7)
+  if(NOT mongoc_FOUND)
+    message(FATAL_ERROR "mongoc or mongoc2 not found! Please install libmongoc-dev.")
+  endif()
+  add_library(mongoc::mongoc ALIAS PkgConfig::mongoc)
+  target_compile_definitions(${module_name} PRIVATE HAVE_LIBMONGOC1)
+endif()
 
 target_link_libraries(${module_name} PRIVATE mongoc::mongoc)