Uses Basis Library equivalent of cd

--- a/src/CCL/ex/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/CCL/ex/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -16,5 +16,5 @@
 time_use_thy "Stream";
 time_use_thy "Flag";
 
-cd "..";
+OS.FileSys.chDir "..";
 maketest"END: Root file for CCL examples";

--- a/src/FOL/ex/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/FOL/ex/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -41,5 +41,5 @@
 time_use_thy "IffOracle";
 
 
-cd "..";
+OS.FileSys.chDir "..";
 maketest"END: Root file for FOL examples";

--- a/src/FOLP/ex/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/FOLP/ex/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -31,5 +31,5 @@
 time_use     "prop.ML";
 time_use     "quant.ML";
 
-cd "..";
+OS.FileSys.chDir "..";
 maketest"END: Root file for FOLP examples";

--- a/src/HOLCF/ex/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/HOLCF/ex/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -16,5 +16,5 @@
 time_use_thy "Fix2";
 time_use "loeckx.ML";
 
-cd "..";
+OS.FileSys.chDir "..";
 maketest     "END: Root file for HOLCF examples";

--- a/src/HOLCF/explicit_domains/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/HOLCF/explicit_domains/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -20,5 +20,5 @@
 time_use_thy "Dagstuhl";
 time_use_thy "Focus_ex";
 
-cd "..";
+OS.FileSys.chDir "..";
 maketest "END: Root file for HOLCF examples: explicit domain axiomatization";

--- a/src/Pure/ROOT.ML	Wed Nov 27 10:31:05 1996 +0100
+++ b/src/Pure/ROOT.ML	Wed Nov 27 10:34:28 1996 +0100
@@ -21,9 +21,9 @@
 use "term.ML";
 
 (*Syntax module*)
-cd "Syntax";
+OS.FileSys.chDir "Syntax";
 use "ROOT.ML";
-cd "..";
+OS.FileSys.chDir "..";
 
 use "type.ML";
 use "sign.ML";
@@ -48,9 +48,9 @@
 structure CPure = struct val thy = Theory.cpure_thy end;
 
 (*Theory parser and loader*)
-cd "Thy";
+OS.FileSys.chDir "Thy";
 use "ROOT.ML";
-cd "..";
+OS.FileSys.chDir "..";
 
 use "install_pp.ML";
 fun init_database () = (init_thy_reader (); init_pps ());