Port ASPELL_DATADIR detection to CMake

Signed-off-by: OBATA Akio <obache@wizdas.com>
(cherry picked from commit ba75e441ea)
Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

CMakeLists.txt

@@ -1144,14 +1144,26 @@ if ( NOT ISPELL_LIBDIR )
 endif ( NOT ISPELL_LIBDIR )
 
 ##### check for aspell ##########################
-# we need ASPELL_DATADIR too
 
 if( WITH_ASPELL )
   find_package( ASPELL )
   if( NOT ASPELL_FOUND )
     message(FATAL_ERROR "\nASPELL support are requested, but not found on your system" )
   endif( NOT ASPELL_FOUND )
+  if( NOT ASPELL_DATADIR )
+    find_program( PSPELL_CONFIG_EXECUTABLE NAMES pspell-config DOC "path to the pspell-config executable" )
+    if( PSPELL_CONFIG_EXECUTABLE )
+      execute_process (
+        COMMAND ${PSPELL_CONFIG_EXECUTABLE} --pkgdatadir
+        OUTPUT_VARIABLE ASPELL_DATADIR
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+    endif( PSPELL_CONFIG_EXECUTABLE )
+  endif( NOT ASPELL_DATADIR )
 endif( WITH_ASPELL )
+if( NOT ASPELL_DATADIR )
+  set ( ASPELL_DATADIR "/usr/lib/aspell" )
+endif( NOT ASPELL_DATADIR )
+set ( ASPELL_DATADIR "${ASPELL_DATADIR}" CACHE PATH "aspell data directory" )
 
 
 ##### check for hspell ##########################