diff --git a/sys-devel/libtool/files/1.5.20/libtool-1.5.20-version-checking.patch b/sys-devel/libtool/files/1.5.20/libtool-1.5.20-version-checking.patch
new file mode 100644
--- /dev/null
+++ b/sys-devel/libtool/files/1.5.20/libtool-1.5.20-version-checking.patch
@@ -0,0 +1,65 @@
+Add a sanity check to make sure the libtool code in the 'configure' script is 
+in sync with the local 'ltmain.sh'.  If they are out of sync, libtool may 
+generate the libraries incorrectly.
+
+http://bugs.gentoo.org/73140
+
+--- libtool-1.5.20/libtool.m4
++++ libtool-1.5.20/libtool.m4
+@@ -212,6 +212,14 @@
+     [pic_mode=default])
+ test -z "$pic_mode" && pic_mode=default
+ 
++# Check if we have a version mismatch between libtool.m4 and ltmain.sh.
++#
++# Note:  This should be in AC_LIBTOOL_SETUP, _after_ $ltmain have been defined.
++#        We also should do it _before_ AC_LIBTOOL_LANG_C_CONFIG that actually
++#        calls AC_LIBTOOL_CONFIG and creates libtool.
++#
++_LT_VERSION_CHECK
++
+ # Use C for the default configuration in the libtool script
+ tagname=
+ AC_LIBTOOL_LANG_C_CONFIG
+@@ -219,6 +227,41 @@
+ ])# AC_LIBTOOL_SETUP
+ 
+ 
++# _LT_VERSION_CHECK
++# -----------------
++AC_DEFUN([_LT_VERSION_CHECK],
++[AC_MSG_CHECKING([for correct ltmain.sh version])
++if test "x$ltmain" = "x" ; then
++  AC_MSG_RESULT(no)
++  AC_MSG_ERROR([
++
++*** @<:@Gentoo@:>@ sanity check failed! ***
++*** \$ltmain is not defined, please check the patch for consistency! ***
++])
++fi
++gentoo_lt_version="@_LT_VERSION@"
++gentoo_ltmain_version=`sed -n '/^[[ 	]]*VERSION=/{s/^[[ 	]]*VERSION=//;p;q;}' "$ltmain"`
++if test "x$gentoo_lt_version" != "x$gentoo_ltmain_version" ; then
++  AC_MSG_RESULT(no)
++  AC_MSG_ERROR([
++
++*** @<:@Gentoo@:>@ sanity check failed! ***
++*** libtool.m4 and ltmain.sh have a version mismatch! ***
++*** (libtool.m4 = $gentoo_lt_version, ltmain.sh = $gentoo_ltmain_version) ***
++
++Please run:
++
++  libtoolize --copy --force
++
++if appropriate, please contact the maintainer of this
++package (or your distribution) for help.
++])
++else
++  AC_MSG_RESULT(yes)
++fi
++])# _LT_VERSION_CHECK
++
++
+ # _LT_AC_SYS_COMPILER
+ # -------------------
+ AC_DEFUN([_LT_AC_SYS_COMPILER],