Add a target with no output so it will always be built.

add_custom_target(Name [ALL] [command1 [args1...]]
                  [COMMAND command2 [args2...] ...]
                  [DEPENDS depend depend depend ... ]
                  [WORKING_DIRECTORY dir]
                  [COMMENT comment] [VERBATIM]
                  [SOURCES src1 [src2...]])

Adds a target with the given name that executes the given commands. The target has no output file and is ALWAYS CONSIDERED OUT OF DATE even if the commands try to create a file with the name of the target. Use ADD_CUSTOM_COMMAND to generate a file with dependencies. By default nothing depends on the custom target. Use ADD_DEPENDENCIES to add dependencies to or from other targets. If the ALL option is specified it indicates that this target should be added to the default build target so that it will be run every time (the command cannot be called ALL). The command and arguments are optional and if not specified an empty target will be created. If WORKING_DIRECTORY is set, then the command will be run in that directory. If it is a relative path it will be interpreted relative to the build tree directory corresponding to the current source directory. If COMMENT is set, the value will be displayed as a message before the commands are executed at build time. Dependencies listed with the DEPENDS argument may reference files and outputs of custom commands created with add_custom_command() in the same directory (CMakeLists.txt file).

If VERBATIM is given then all arguments to the commands will be escaped properly for the build tool so that the invoked command receives each argument unchanged. Note that one level of escapes is still used by the CMake language processor before add_custom_target even sees the arguments. Use of VERBATIM is recommended as it enables correct behavior. When VERBATIM is not given the behavior is platform specific because there is no protection of tool-specific special characters.

The SOURCES option specifies additional source files to be included in the custom target. Specified source files will be added to IDE project files for convenience in editing even if they have not build rules.