make sure this autoreconf's properly

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@13698 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/ilbc/configure.ac

@@ -64,6 +64,7 @@ AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_GCC_TRADITIONAL
 AC_PROG_LIBTOOL
+AC_PROG_INSTALL
 AC_LANG([C])
 
 AX_COMPILER_VENDOR