more IO_ERROR constructor fixes

new/sch_dir_lib_source.cpp

@@ -362,7 +362,7 @@ DIR_LIB_SOURCE::DIR_LIB_SOURCE( const STRING& aDirectoryPath,
 
     if( sourceURI.size() == 0 )
     {
-        throw( IO_ERROR( "aDirectoryPath cannot be empty" ) );
+        throw( IO_ERROR( STRING("aDirectoryPath cannot be empty") ) );
     }
 
     // remove any trailing separator, so we can add it back later without ambiguity

new/sch_lib_table.cpp

@@ -134,12 +134,13 @@ void LIB_TABLE::Parse( SCH_LIB_TABLE_LEXER* in ) throw( IO_ERROR )
         // before any fall back.
         if( !InsertRow( row ) )
         {
-            char    buf[300];
+            STRING msg;
 
-            snprintf( buf, sizeof(buf),
-                "'%s' is a duplicate logical lib name",
-                row->logicalName.c_str() );
-            throw IO_ERROR( buf );
+            msg += '\'';
+            msg += row->logicalName;
+            msg += '\'';
+            msg += " is a duplicate logical lib name";
+            throw IO_ERROR( msg );
         }
     }
     return;