* fixed test

tests/webtbs/tw0869.pp

@@ -1,5 +1,5 @@
 program prueba;
-uses crt;
+uses crt,math;
 var
  i,resultado,exponente:integer;
 begin

tests/webtbs/tw0937.pp

@@ -1,7 +1,7 @@
 program test_0_to_power_6;
 
 uses
-  crt;
+  crt,math;
 var
  result,number,exponent : integer;
 begin

tests/webtbs/tw1792.pp

@@ -1,3 +1,5 @@
+uses
+  math;
 Begin
  WriteLn(power(2,31));
 end.