MDEV-19129: Fixed configure for Xcode, CMake generate

CMake Error in wsrep-lib/CMakeLists.txt:
  The custom command generating

    /Users/name/build/mariadb-server/sql/lex_token.h

  is attached to multiple targets:

    GenServerSource
    sql

  but none of these is a common dependency of the other(s).  This is not
  allowed by the Xcode "new build system".

sql/CMakeLists.txt

@@ -351,6 +351,7 @@ ADD_CUSTOM_TARGET(
         GenServerSource
         DEPENDS ${GEN_SOURCES}
 )
+ADD_DEPENDENCIES(sql GenServerSource)
 
 #Need this only for embedded
 SET_TARGET_PROPERTIES(GenServerSource PROPERTIES EXCLUDE_FROM_ALL TRUE)