cmVersionMacros: Adopt CMake_VERSION_DEVEL

Rename it from DEVEL_CMAKE_VERSION.  It requires version macros
not guaranteed to be available from its old header anyway.

Help/dev/maint.rst

@@ -263,12 +263,12 @@ Update ``Source/CMakeVersion.cmake`` to set the version to
   set(CMake_VERSION_PATCH 0)
   set(CMake_VERSION_RC 0)
 
-Replace uses of ``DEVEL_CMAKE_VERSION`` in the source tree with
+Replace uses of ``CMake_VERSION_DEVEL`` in the source tree with
 the literal release version number string ``"$major.$minor.0"``:
 
 .. code-block:: shell
 
-  $EDITOR $(git grep -l DEVEL_CMAKE_VERSION)
+  $EDITOR $(git grep -l CMake_VERSION_DEVEL)
 
 Commit with a message such as::
 

Source/cmExportFileGenerator.h

@@ -18,16 +18,6 @@ class cmExportSet;
 class cmGeneratorTarget;
 class cmLocalGenerator;
 
-#define STRINGIFY_HELPER(X) #X
-#define STRINGIFY(X) STRINGIFY_HELPER(X)
-
-#define DEVEL_CMAKE_VERSION(major, minor)                                     \
-  (CMake_VERSION_ENCODE(major, minor, 0) >                                    \
-       CMake_VERSION_ENCODE(CMake_VERSION_MAJOR, CMake_VERSION_MINOR, 0)      \
-     ? STRINGIFY(CMake_VERSION_MAJOR) "." STRINGIFY(                          \
-         CMake_VERSION_MINOR) "." STRINGIFY(CMake_VERSION_PATCH)              \
-     : #major "." #minor ".0")
-
 /** \class cmExportFileGenerator
  * \brief Generate files exporting targets from a build or install tree.
  *

Source/cmVersionMacros.h

@@ -18,3 +18,13 @@
   ((((major) * 1000u) * CMake_VERSION_ENCODE_BASE) +                          \
    (((minor) % 1000u) * CMake_VERSION_ENCODE_BASE) +                          \
    (((patch) % CMake_VERSION_ENCODE_BASE)))
+
+#define CMV_STRINGIFY(X) CMV_STRINGIFY_DELAY(X)
+#define CMV_STRINGIFY_DELAY(X) #X
+
+#define CMake_VERSION_DEVEL(major, minor)                                     \
+  (CMake_VERSION_ENCODE(major, minor, 0) >                                    \
+       CMake_VERSION_ENCODE(CMake_VERSION_MAJOR, CMake_VERSION_MINOR, 0)      \
+     ? CMV_STRINGIFY(CMake_VERSION_MAJOR) "." CMV_STRINGIFY(                  \
+         CMake_VERSION_MINOR) "." CMV_STRINGIFY(CMake_VERSION_PATCH)          \
+     : #major "." #minor ".0")