compile should be warning-free (x64)

[shuffle2]

When compiling mbedtls-1.4 with VS2015 targeting amd64 with default config.h, the following warnings are reported:

1>  x509_crl.c
mbedtls\library\ssl_srv.c(1429): warning C4267: '=': conversion from 'size_t' to 'unsigned int', possible loss of data
mbedtls\library\ssl_srv.c(1538): warning C4267: '-=': conversion from 'size_t' to 'unsigned int', possible loss of data
mbedtls\library\ssl_tls.c(1555): warning C4267: 'initializing': conversion from 'size_t' to 'unsigned char', possible loss of data
1>  x509_crt.c
1>  x509_csr.c
mbedtls\library\net.c(205): warning C4267: 'function': conversion from 'size_t' to 'int', possible loss of data
mbedtls\library\ssl_tls.c(5834): warning C4267: 'return': conversion from 'size_t' to 'int', possible loss of data
mbedtls\library\ssl_tls.c(5841): warning C4267: '=': conversion from 'size_t' to 'int', possible loss of data
mbedtls\library\ssl_tls.c(5846): warning C4267: '=': conversion from 'size_t' to 'int', possible loss of data
mbedtls\library\ssl_tls.c(5854): warning C4267: 'return': conversion from 'size_t' to 'int', possible loss of data
mbedtls\library\net.c(304): warning C4267: 'function': conversion from 'size_t' to 'int', possible loss of data
1>  x509write_crt.c
mbedtls\library\net.c(455): warning C4133: 'function': incompatible types - from 'int *' to 'char *'

All except the last one (C4133) also occurred on VS2013. The size_t warnings, at least, should be taken care of.

[mpg]

Thanks for your report! I just fixed all warnings from VS2015 on Win64 in the upcoming 2.0.