cmake BSON_HAVE_STRINGS_H examples

cvet/fonline ThirdParty/mongo-c-driver/src/libbson/CMakeLists.txt :96 

check_include_file (strings.h BSON_HAVE_STRINGS_H)

realm/realm-core src/external/bson/CMakeLists.txt :37 

check_include_file (strings.h BSON_HAVE_STRINGS_H)