Test with 32-bit and 64-bit bignum limbs on all architectures
Test with 32-bit and 64-bit bignum limbs on all architectures

Build with MBEDTLS_HAVE_INT32 and MBEDTLS_HAVE_INT64 on all
architectures, not just x86_64. These two modes should work on all
platforms (except embedded environments where 64-bit division is not
available).

Also run the unit tests.

Correct the description: this is not "N-bit compilation", but "N-bit
bignum limbs".

ARMmbed/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls