message: Fix empty 'version' file
  This teaches the makefiles to construct the version string again so
  it can be emitted to the 'version' file for packaging.
  Fixes failing nightly builds.
diff: @@ -9,12 +9,16 @@ include config.mk
  export PATH := $(dir $(CFG_RUSTC)):$(PATH)
  ifeq ($(CFG_RELEASE_CHANNEL),stable)
  +CFG_RELEASE=$(CFG_RELEASE_NUM)
  CFG_PACKAGE_VERS=$(CFG_RELEASE_NUM)
  else ifeq ($(CFG_RELEASE_CHANNEL),beta)
  +CFG_RELEASE=$(CFG_RELEASE_NUM)-beta
  CFG_PACKAGE_VERS=beta
  else ifeq ($(CFG_RELEASE_CHANNEL),nightly)
  +CFG_RELEASE=$(CFG_RELEASE_NUM)-nightly
  CFG_PACKAGE_VERS=nightly
  else ifeq ($(CFG_RELEASE_CHANNEL),dev)
  +CFG_RELEASE=$(CFG_RELEASE_NUM)-dev
  CFG_PACKAGE_VERS=$(CFG_RELEASE_NUM)-dev
  endif
  @@ -57,13 +61,15 @@ CFG_VERSION_MAJOR := $(word 1,$(CFG_RELEASE_PARTS))
  CFG_VERSION_MINOR := $(word 2,$(CFG_RELEASE_PARTS))
  CFG_VERSION_PATCH := $(word 3,$(CFG_RELEASE_PARTS))
  -export CFG_VERSION
  +# This is output to the 'version' file during packaging
  +CFG_VERSION=$(CFG_RELEASE)
  +ifneq ($(CFG_COMMIT_HASH),)
  +CFG_VERSION=$(CFG_RELEASE) ($(CFG_SHORT_COMMIT_HASH) $(CFG_COMMIT_DATE))
  +endif
  +
  export CFG_VERSION_MAJOR
  export CFG_VERSION_MINOR
  export CFG_VERSION_PATCH
  -ifneq ($(CFG_PRERELEASE_VERSION),)
  -export CFG_PRERELEASE_VERSION
  -endif
  ifneq ($(CFG_COMMIT_HASH),)
  export CFG_COMMIT_HASH
  export CFG_COMMIT_DATE
  