add HDF4 library version in the configure output.

CMakeLists.txt

@@ -349,6 +349,12 @@ if (nexus)
       message(FATAL_ERROR "HDF4 library not found. Please install libhdf4-dev or hdf-devel")
     endif()
 
+    #--- try to extract the HDF4 version from H4config.h (autotools builds) --------
+    if (EXISTS "${HDF4_INCLUDE_DIR}/H4config.h")
+      file(STRINGS "${HDF4_INCLUDE_DIR}/H4config.h" HDF4_VERSION_LINE REGEX "^#define[ \t]+H4_VERSION[ \t]+\"[^\"]*\"")
+      string(REGEX REPLACE "^#define[ \t]+H4_VERSION[ \t]+\"([^\"]*)\".*" "\\1" HDF4_VERSION "${HDF4_VERSION_LINE}")
+    endif ()
+
     # HDF4 4.4.0 changed the Vgetname() prototype from
     #   int32 Vgetname(int32 vkey, char *vgname)
     # to
@@ -497,7 +503,7 @@ endif (OpenMP_FOUND)
 if (nexus)
   message("")
   if (HAVE_HDF4)
-    message(" HDF4    found in ${HDF4_INCLUDE_DIRS}")
+    message(" HDF4    found in ${HDF4_INCLUDE_DIRS}, Version: ${HDF4_VERSION}")
   else (HAVE_HDF4)
     message(" HDF4    not present.")	  
   endif (HAVE_HDF4)