libxml2: Fix build when DISTRO_FEATURES lacks "largefile".

libxml2: Fix build when DISTRO_FEATURES lacks "largefile".

mipsel-oe-linux-uclibc-libtool: compile:  mipsel-oe-linux-uclibc-gcc -march=mips32 -DHAVE_CONFIG_H -I. -I./include -I./include -D_REENTRANT -isystem/mnt/oe/tmp/sysroots/mipsel-oe-linux-uclibc/include -isystem/mnt/oe/tmp/sysroots/mipsel-oe-linux-uclibc/include -fexpensive-optimizations -fomit-frame-pointer -frename-registers -Os -pedantic -W -Wformat -Wunused -Wimplicit -Wreturn-type -Wswitch -Wcomment -Wtrigraphs -Wformat -Wchar-subscripts -Wuninitialized -Wparentheses -Wshadow -Wpointer-arith -Wcast-align -Wwrite-strings -Waggregate-return -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Winline -Wredundant-decls -MT xmlIO.lo -MD -MP -MF .deps/xmlIO.Tpo -c xmlIO.c  -fPIC -DPIC -o .libs/xmlIO.o
In file included from /mnt/oe/tmp/sysroots/mipsel-oe-linux-uclibc/include/stdio.h:72:0,
                 from libxml.h:44,
                 from encoding.c:24:
/mnt/oe/tmp/sysroots/mipsel-oe-linux-uclibc/include/bits/uClibc_stdio.h:61:2: error: #error Sorry... uClibc was built without large file support!

Signed-off-by: Graham Gower <graham.gower@gmail.com>
Signed-off-by: Eric Bénard <eric@eukrea.com>