fix some gcc warnings (#73) * tweak string size fix gcc8 warnings ``` svr-agentfwd.c: In function 'bindagent': svr-agentfwd.c:254:53: warning: '%s' directive output may be truncated writing up to 107 bytes into a region of size between 0 and 107 [-Wformat-truncation=] snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s", path, sockfile); ^~ ~~~~~~~~ svr-agentfwd.c:254:2: note: 'snprintf' output between 2 and 216 bytes into a destination of size 108 snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s", path, sockfile); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``` * cleanup signed/unsigned comparison fix gcc8 warnings ``` scp.c: In function 'do_local_cmd': scp.c:132:17: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] for (i = 0; i < a->num; i++) ^ scpmisc.c: In function 'addargs': scpmisc.c:161:25: warning: comparison of integer expressions of different signedness: 'int' and 'u_int' {aka 'unsigned int'} [-Wsign-compare] } else if (args->num+2 >= nalloc) ^~ scpmisc.c: In function 'replacearg': scpmisc.c:183:12: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] if (which >= args->num) ^~ scpmisc.c: In function 'freeargs': scpmisc.c:196:17: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] for (i = 0; i < args->num; i++) ^ ``` see https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/misc.h.diff?r1=1.16&r2=1.17

/* compile options depend on Dropbear options.h */
#include "options.h"

/* Dropbear config */

#define LTC_NOTHING

/* Use small code where possible */
#if DROPBEAR_SMALL_CODE
#define LTC_SMALL_CODE
#endif

#if DROPBEAR_BLOWFISH
#define LTC_BLOWFISH
#endif
#if DROPBEAR_AES
#define LTC_RIJNDAEL
#endif
/* _TABLES tells it to use tables during setup, _SMALL means to use the smaller scheduled key format
 * (saves 4KB of ram), _ALL_TABLES enables all tables during setup */
#if DROPBEAR_TWOFISH
#define LTC_TWOFISH
#define LTC_TWOFISH_SMALL
#endif

#if DROPBEAR_3DES
#define LTC_DES
#endif

#if DROPBEAR_ENABLE_CTR_MODE
#define LTC_CBC_MODE
#endif

#if DROPBEAR_ENABLE_CTR_MODE
#define LTC_CTR_MODE
#endif


#if DROPBEAR_SHA512
#define LTC_SHA512
#endif

#if DROPBEAR_SHA384
#define LTC_SHA384
#endif

#if DROPBEAR_SHA256
#define LTC_SHA256
#endif

#define LTC_SHA1

#if DROPBEAR_MD5
#define LTC_MD5
#endif

/* ECC */
#if DROPBEAR_ECC
#define LTC_MECC
#define LTM_DESC

/* use Shamir's trick for point mul (speeds up signature verification) */
#define LTC_ECC_SHAMIR

#if DROPBEAR_ECC_256
#define LTC_ECC256
#endif
#if DROPBEAR_ECC_384
#define LTC_ECC384
#endif
#if DROPBEAR_ECC_521
#define LTC_ECC521
#endif

#endif /* DROPBEAR_ECC */

#define LTC_HMAC
#define LTC_HASH_HELPERS

#define LTC_NO_TEST

#define LTC_BASE64

/* end Dropbear config */