cmake EVENT__HAVE_STRING_H examples

GreatSQL/GreatSQL extra/libevent/libevent-2.1.11-stable/CMakeLists.txt :465 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

percona/percona-server extra/libevent/libevent-2.1.11-stable/CMakeLists.txt :473 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

facebook/mysql-5.6 extra/libevent/libevent-2.1.11-stable/CMakeLists.txt :465 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

nmathewson/libevent_obsolete CMakeLists.txt :319 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

polardb/polardbx-engine extra/libevent/libevent-2.1.11-stable/CMakeLists.txt :465 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

fluent/fluent-bit lib/monkey/mk_core/deps/libevent/CMakeLists.txt :273 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)

percona/percona-xtradb-cluster extra/libevent/libevent-2.1.11-stable/CMakeLists.txt :465 

CHECK_INCLUDE_FILE(string.h EVENT__HAVE_STRING_H)