Add support for multiline messages in tde_message_* macros

Also convert tde_message_author_warning() to a function to not pollute
caller's environment.

Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

modules/TDEMacros.cmake

@@ -86,16 +86,29 @@ include( CheckTypeSize )
 include( TDEVersion )
 
 
+#################################################
+#####
+##### tde_concat_msg
+
+macro( tde_concat_msg _msg )
+  unset( ${_msg} )
+  foreach( _arg ${ARGN} )
+    string( APPEND ${_msg} " ${_arg}\n" )
+  endforeach()
+endmacro( tde_concat_msg )
+
+
 #################################################
 #####
 ##### tde_message_author_warning
 
-macro( tde_message_author_warning )
+function( tde_message_author_warning )
+  tde_concat_msg( _msg ${ARGV} )
   message( AUTHOR_WARNING
     "-------------------------------------------------\n"
-    " ${ARGV}\n"
+    "${_msg}"
     "-------------------------------------------------" )
-endmacro( tde_message_author_warning )
+endfunction( tde_message_author_warning )
 
 
 #################################################
@@ -103,9 +116,11 @@ endmacro( tde_message_author_warning )
 ##### tde_message_fatal
 
 macro( tde_message_fatal )
+  tde_concat_msg( _msg ${ARGV} )
+
   message( FATAL_ERROR
     "#################################################\n"
-    " ${ARGV}\n"
+    "${_msg}"
     "#################################################" )
 endmacro( tde_message_fatal )