build: various build improvements

- remove "ran-" prefix from touch files as it's redundant since the
  they're already in the directory named `touches`.
- Include `contrib` when formatting with `make formatlua`.
- Use TARGET_FILE generator expression instead of assuming the
  executable location.
- reuse logic that determines whether to use lua or luajit.
- add translations to the `nvim` target.

Makefile improvements:
- rename variable `CMAKE_PRG` to `CMAKE` to make it more consistent with
  the builtin `MAKE` variable.
- stop propagating flags to generator. Users should use cmake for
  non-standard use cases.
- remove `+` prefix from targets. If the user for whatever reason wants
  to dry-run a target then they should be able to.

src/nvim/CMakeLists.txt

@@ -3,12 +3,12 @@ add_library(main_lib INTERFACE)
 # Internally we need to make a distinction between "nvim without runtime files"
 # (nvim_bin) and "nvim with runtime files" (nvim).
 add_executable(nvim_bin EXCLUDE_FROM_ALL)
-set_target_properties(nvim_bin PROPERTIES OUTPUT_NAME nvim)
 
 set_target_properties(nvim_bin
   PROPERTIES
   EXPORT_COMPILE_COMMANDS ON
-  ENABLE_EXPORTS TRUE)
+  ENABLE_EXPORTS TRUE
+  OUTPUT_NAME nvim)
 
 #-------------------------------------------------------------------------------
 # Dependencies

src/nvim/po/CMakeLists.txt

@@ -182,6 +182,7 @@ if(HAVE_WORKING_LIBINTL AND GETTEXT_FOUND AND XGETTEXT_PRG AND ICONV_PRG)
     BuildMo(${LANGUAGE})
   endforeach()
 
-  add_custom_target(nvim_translations ALL DEPENDS ${LANGUAGE_MO_FILES})
+  add_custom_target(nvim_translations DEPENDS ${LANGUAGE_MO_FILES})
   add_custom_target(update-po DEPENDS ${UPDATE_PO_TARGETS})
+  add_dependencies(nvim nvim_translations)
 endif()