Defines starting with `s' in common

• SERPENT_KS common/crypto.h:156
• SERPENT_TEST_COUNT common/tests.c:400
• SHA1_BLOCKSIZE common/crypto.h:69
• SHA1_DIGESTSIZE common/crypto.h:70
• SHA512_BLOCKSIZE common/crypto.h:72
• SHA512_DIGESTSIZE common/crypto.h:73
• S_IFDIR common/keyfiles.c:29
• SIZEOF_MRU_LIST common/combo.c:19
• snprintf common/keyfiles.c:30
• stat common/keyfiles.c:28
• SWAP_BYTES common/gfmul.c:106