MBEDTLS_GCM_C macro

\def MBEDTLS_GCM_C Enable the Galois/Counter Mode (GCM). Module: library/gcm.c Requires: MBEDTLS_CIPHER_C, MBEDTLS_AES_C or MBEDTLS_CAMELLIA_C or MBEDTLS_ARIA_C This module enables the AES-GCM and CAMELLIA-GCM ciphersuites, if other requisites are enabled as well.