Fix 'format not a string literal' error

Thanks to Francois Andriot for the patch

src/cassembler.cpp

@@ -575,7 +575,7 @@ bool CAssembler::exportVHDL( string templateFile, string outputDir, string entit
 					for( j = 31 ; j >= 0 ; j-- )
 		 				fprintf( outfile, "%02X", INITP[ j ][ line ] ) ;
 			} else if ( strcmp( "name", varname ) == 0 ) {
-				fprintf( outfile, entityName.c_str() ) ;				
+				fprintf( outfile, "%s", entityName.c_str() ) ;				
 			} else if ( strcmp( "begin template", varname ) == 0 ) {
 				copy = true ;
 			}