Mp4: fixed setting wrong mdat atom size in very rare cases. Atom size is the sum of atom header size and atom data size. The specification says that the first 4 bytes are set to one when the atom size is greater than the maximum unsigned 32-bit value. Which means atom header size should be considered when the comparison takes place between atom data size and 0xffffffff.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


# aCC: HP ANSI C++ B3910B A.03.55.02

# C89 mode

CFLAGS="$CFLAGS -Ae"
CC_TEST_FLAGS="-Ae"

PCRE_OPT="$PCRE_OPT -Ae"
ZLIB_OPT="$ZLIB_OPT -Ae"