Same as in bug 10030.

AM_CONFIG_HEADER shouldn't be used anymore and it used to be a warning for a long time, now it's fatal error with automake-1.13:

aclocal-1.13: warning: autoconf input should be named 'configure.ac', not 'configure.in'
configure.in:32: error: 'AM_CONFIG_HEADER': this macro is obsolete.
    You should use the 'AC_CONFIG_HEADERS' macro instead.
/usr/share/aclocal-1.13/obsolete-err.m4:12: AM_CONFIG_HEADER is expanded from...
configure.in:32: the top level
autom4te-2.69: /usr/bin/m4 failed with exit status: 1
aclocal-1.13: error: echo failed with exit status: 1

The fix is simple:

sed -i -e 's:AM_CONFIG_HEADER:AC_CONFIG_HEADERS:' configure.in.in

As in, replace AM_CONFIG_HEADER with AC_CONFIG_HEADERS in configure.in.in (notice it's HEADERS, not HEADER)

(Why not use the modern name, configure.ac instead of configure.in while at it?)