Add support for a user specified strip application via configure.

Signed-off-by: Garrett Cooper <yanegomi@gmail.com>
diff --git a/configure.ac b/configure.ac
index 899d03e..020f2f9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,6 +23,8 @@
 AC_PROG_AR
 AC_PROG_LEX
 AC_PROG_RANLIB
+AC_DEFUN([AC_PROG_STRIP], [AC_CHECK_TOOL(STRIP, strip, :)])
+AC_PROG_STRIP
 AC_PROG_YACC
 
 AC_PREFIX_DEFAULT(/opt/ltp)