we already patch the python modules behind the python-config scripts,
but the shell python-config script is completely unrelated.

we throw away the -L$libdir path because $libdir is in the toolchain's
search path already, so we don't need the redundancy.

--- a/Misc/python-config.sh.in
+++ b/Misc/python-config.sh.in
@@ -25,6 +25,9 @@ installed_prefix ()
 }
 
 prefix_real=$(installed_prefix "$0")
+if [ "${prefix_real}" = "/usr" ]; then
+  prefix_real="${SYSROOT}/usr"
+fi
 
 # Use sed to fix paths from their built-to locations to their installed-to
 # locations. Keep prefix & exec_prefix using their original values in case
@@ -97,7 +100,7 @@ do
             echo "$LIBS"
         ;;
         --ldflags)
-            echo "-L$libdir $LIBS"
+            echo "$LIBS"
         ;;
         --extension-suffix)
             echo "$SO"