* use Sysutils for not fpc compilers

tests/test/units/system/trdtxt01.pp

@@ -1,6 +1,12 @@
 Program trdtxt01;
 
-uses strings;
+{$ifdef fpc}
+uses
+  strings;
+{$else}
+uses
+  SysUtils;
+{$endif}
 
 procedure test(b: boolean);
 begin

tests/test/units/system/trdtxt02.pp

@@ -1,6 +1,12 @@
 Program trdtxt02;
 
-uses strings;
+{$ifdef fpc}
+uses
+  strings;
+{$else}
+uses
+  SysUtils;
+{$endif}
 
 procedure test(b: boolean);
 begin

tests/test/units/system/trdtxt03.pp

@@ -1,6 +1,12 @@
 Program trdtxt03;
 
-uses strings;
+{$ifdef fpc}
+uses
+  strings;
+{$else}
+uses
+  SysUtils;
+{$endif}
 
 procedure test(b: boolean);
 begin