disable shared libraries on 32-bit 10.6

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@10338 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

configure

@@ -576,7 +576,16 @@ if test $withsharedlibs = "yes"; then
       byteccrpath="-Wl,-rpath,"
       mksharedlibrpath="-rpath "
       shared_libraries_supported=true;;
-    i[3456]86-*-darwin[4-9]*)
+    i[3456]86-*-darwin10.*)
+      if test $arch64 == true; then
+          mksharedlib="$bytecc -bundle -flat_namespace -undefined suppress"
+          bytecccompopts="$dl_defs $bytecccompopts"
+          dl_needs_underscore=false
+          shared_libraries_supported=true
+      else
+          shared_libraries_supported=false
+      fi;;
+    i[3456]86-*-darwin*)
       mksharedlib="$bytecc -bundle -flat_namespace -undefined suppress -read_only_relocs suppress"
       bytecccompopts="$dl_defs $bytecccompopts"
       dl_needs_underscore=false