make some arrays const

this way they'll go into .rodata, decreasing memory pressure.

src/crypt/crypt_md5.c

@@ -182,7 +182,7 @@ static void md5_update(struct md5 *s, const void *m, unsigned long len)
 #define KEY_MAX 30000
 #define SALT_MAX 8
 
-static unsigned char b64[] =
+static const unsigned char b64[] =
 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 static char *to64(char *s, unsigned int u, int n)

src/crypt/crypt_sha256.c

@@ -153,7 +153,7 @@ static void sha256_update(struct sha256 *s, const void *m, unsigned long len)
 	memcpy(s->buf, p, len);
 }
 
-static unsigned char b64[] =
+static const unsigned char b64[] =
 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 static char *to64(char *s, unsigned int u, int n)

src/crypt/crypt_sha512.c

@@ -174,7 +174,7 @@ static void sha512_update(struct sha512 *s, const void *m, unsigned long len)
 	memcpy(s->buf, p, len);
 }
 
-static unsigned char b64[] =
+static const unsigned char b64[] =
 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
 static char *to64(char *s, unsigned int u, int n)