MDEV-21303 Make executables MariaDB named

To change all executables to have a mariadb name I had to:
- Do name changes in every CMakeLists.txt that produces executables
- CREATE_MARIADB_SYMLINK was removed and GET_SYMLINK added by Wlad to reuse the function in other places also
- The scripts/CMakeLists.txt could make use of GET_SYMLINK instead of introducing redundant code, but I thought I'll leave that for next release
- A lot of changes to debian/.install and debian/.links files due to swapping of real executable and symlink. I did not however change the name of the manpages, so the real name is still mysql there and mariadb are symlinks.
- The Windows part needed a change now when we made the executables mariadb -named. MSI (and ZIP) do not support symlinks and to not break backward compatibility we had to include mysql named binaries also. Done by Wlad

cmake/mysql_add_executable.cmake

@@ -1,5 +1,5 @@
 # Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
-# 
+#
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; version 2 of the License.
@@ -36,7 +36,7 @@ FUNCTION (MYSQL_ADD_EXECUTABLE)
   )
   LIST(GET ARG_UNPARSED_ARGUMENTS 0 target)
   LIST(REMOVE_AT  ARG_UNPARSED_ARGUMENTS 0)
-  
+
   SET(sources ${ARG_UNPARSED_ARGUMENTS})
   ADD_VERSION_INFO(${target} EXECUTABLE sources)
 
@@ -62,6 +62,7 @@ FUNCTION (MYSQL_ADD_EXECUTABLE)
   ELSE()
     UNSET(EXCLUDE_FROM_ALL)
   ENDIF()
+
   ADD_EXECUTABLE(${target} ${WIN32} ${MACOSX_BUNDLE} ${EXCLUDE_FROM_ALL} ${sources})
 
   # tell CPack where to install
@@ -79,16 +80,44 @@ FUNCTION (MYSQL_ADD_EXECUTABLE)
     IF (COMP MATCHES ${SKIP_COMPONENTS})
       RETURN()
     ENDIF()
-    IF (WITH_STRIPPED_CLIENT AND NOT target STREQUAL mysqld)
+
+    IF (WITH_STRIPPED_CLIENT AND NOT target STREQUAL mariadbd)
       INSTALL(CODE "SET(CMAKE_INSTALL_DO_STRIP 1)" COMPONENT ${COMP})
       SET(reset_strip ON)
     ENDIF()
+
     MYSQL_INSTALL_TARGETS(${target} DESTINATION ${ARG_DESTINATION} COMPONENT ${COMP})
+    
     IF (reset_strip)
       INSTALL(CODE "SET(CMAKE_INSTALL_DO_STRIP 0)" COMPONENT ${COMP})
     ENDIF()
   ENDIF()
 
-  # create mariadb named symlink
-  CREATE_MARIADB_SYMLINK(${target} ${ARG_DESTINATION} ${COMP})
+  # create MySQL named "legacy links"
+  GET_SYMLINK(${target} link)
+  IF(link)
+    IF(UNIX)
+      ADD_CUSTOM_COMMAND(TARGET ${target} POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E create_symlink
+         ${target} ${link}
+        COMMENT "Creating ${link} link"
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR})
+      INSTALL(PROGRAMS
+         ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/${link}
+         DESTINATION
+         ${ARG_DESTINATION}
+         COMPONENT ${COMP})
+    ELSE()
+      # Windows note:
+      # Here, hardlinks are used, because cmake can't install symlinks.
+      # In packages, there are won't be links, just copies.
+      SET(link ${link}.exe)
+      ADD_CUSTOM_COMMAND(TARGET ${target} POST_BUILD
+        COMMAND cmake -E remove -f ${link}
+        COMMAND mklink /H ${link} $<TARGET_FILE_NAME:${target}>
+        COMMENT "Creating ${link} link"
+        WORKING_DIRECTORY $<TARGET_FILE_DIR:${target}>)
+      INSTALL(PROGRAMS $<TARGET_FILE_DIR:${target}>/${link} DESTINATION ${ARG_DESTINATION} COMPONENT ${COMP})
+    ENDIF()
+  ENDIF()
 ENDFUNCTION()