* use heapsize-memavail to check used mem

tests/webtbs/tw0813.pp

@@ -17,11 +17,11 @@ end;
 
 var MemBefore : longint;
 begin
-  writeln(MemAvail);
-  MemBefore:=MemAvail;
+  writeln(heapsize-MemAvail);
+  MemBefore:=heapsize-MemAvail;
   Test;
-  writeln(MemAvail);
-  if MemBefore<>MemAvail then
+  writeln(heapsize-MemAvail);
+  if MemBefore<>heapsize-MemAvail then
     begin
       Writeln('ReAllocMem creates emory leaks');
       Writeln('Bug 812 is not yet fixed');

tests/webtbs/tw1658.pp

@@ -34,7 +34,7 @@ var
   EntryMem,ExitMem : Cardinal;
 // Main routine
 begin
-  EntryMem:=MemAvail;
+  EntryMem:=heapsize-MemAvail;
   pTempStream := nil;
   pTempStream := New(PMyStream, Init('tw1658.tmp', stCreate));
   if not Assigned(pTempStream) then
@@ -42,7 +42,7 @@ begin
   pTempStream^.m_fAutoDelete := False;
   Dispose(pTempStream, Done);
   pTempStream := nil;
-  ExitMem:=MemAvail;
+  ExitMem:=heapsize-MemAvail;
   If ExitMem<EntryMem then
     begin
       Writeln('Memory lost');

tests/webtbs/uw0701d.pp

@@ -8,9 +8,9 @@ var
    startmem : longint;
 
 initialization
-   startmem:=memavail;
+   startmem:=heapsize-memavail;
 finalization
-   if startmem<>memavail then
+   if startmem<>heapsize-memavail then
      begin
        writeln('Problem with ansistrings in units');
        halt(1);