CMake: add demo target

CMakeLists.txt

@@ -605,6 +605,11 @@ install(TARGETS notcurses-tester DESTINATION bin)
 endif()
 endif()
 
+add_custom_target(demo
+  COMMAND ./notcurses-demo -p ${CMAKE_CURRENT_SOURCE_DIR}/data -c
+  DEPENDS notcurses-demo
+)
+
 # pkg-config support
 configure_file(tools/notcurses.pc.in
   ${CMAKE_CURRENT_BINARY_DIR}/notcurses.pc

README.md

@@ -145,7 +145,7 @@ test failures, *please* file a bug including the output of
 
 (`make test` also runs `notcurses-tester`, but hides important output).
 
-To watch the bitchin' demo, run `./notcurses-demo -p ../data`. More details can
+To watch the bitchin' demo, run `make demo`. More details can
 be found on the `notcurses-demo(1)` man page.
 
 Install with `make install` following a successful build. This installs the C