--- ltmain.sh
+++ ltmain.sh
@@ -136,6 +136,30 @@
 execute_dlfiles=
 lo2o="s/\\.lo\$/.${objext}/"
 o2lo="s/\\.${objext}\$/.lo/"
+
+if test -z "$max_cmd_len"; then
+  i=0
+  testring="ABCD"
+  new_result=
+  
+  # If test is not a shell built-in, we'll probably end up computing a
+  # maximum length that is only half of the actual maximum length, but
+  # we can't tell.
+  while (test "X"`$SHELL $0 --fallback-echo "X$testring" 2>/dev/null` \
+             = "XX$testring") >/dev/null 2>&1 &&
+          new_result=`expr "X$testring" : ".*" 2>&1` &&
+          max_cmd_len="$new_result" &&
+          test "$i" != 17 # 1/2 MB should be enough
+  do
+    i=`expr $i + 1`
+    testring="$testring$testring"
+  done
+  testring=
+  # Add a significant safety factor because C++ compilers can tack on massive
+  # amounts of additional arguments before passing them to the linker.
+  # It appears as though 1/2 is a usable value.
+  max_cmd_len=`expr $max_cmd_len \/ 2`
+fi
 
 #####################################
 # Shell function definitions: