Among many fixes and improvements this new version adds
support of ARC architecture (ARC port was actually introduced
in v3.1 but while at it why not to update to the most recent version).
Which allows to build dependent projects like Python etc.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

My last commit c1137b6db7 "libffi: fix
libffi.pc file" broke the host build as that still placed the header
files to /usr/lib/libffi-3.0.13/include/ and the libffi.pc file pointed
to /usr/include/ . With this patch I took the patch from Debian and
also made the install process to put the header files to /usr/include
in all situations.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

The include dir pointed to staging_dir/target-mips_34kc+dsp_musl-1.1.11
/usr/lib/libffi-3.0.13/include which does not exists, this made glib2
fail to compile. The header files are copied to /usr/include so define
it in the libffi.pc file.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>