Release 2.3.1 does not compile for 32 bit targets

[pekfos]

Hello,
when I try to compile release 2.3.1 (or master) for 32-bit ARM, following error occurs:

c_rtp.h:113:1: error: static assertion failed: "sc_rtp_context length should be multiple of 8 bytes"
 _Static_assert((sizeof(struct sc_rtp_context) % 8) == 0,

When I comment out all static asserts (since they say 'should' and would not be even there for compilers not supporting them), most of tests fail. The compiler is GCC linaro 5.4.0. Everything works fine with regular GCC 5.4.0 targeting x86-64, but you can still reproduce problem with -m32 flag.

Steps to reproduce:
1. autoreconf -i -f
2. CFLAGS=-m32 ./configure
3. make

Don't know if step one is relevant to the problem. It appears that configure does not work out-of-the box:
configure: error: cannot find install-sh, install.sh, or shtool in "." "./.." "./../.."