Add use of asprintf()

Add asprintf(), pg_asprintf(), and psprintf() to simplify string
allocation and composition.  Replacement implementations taken from
NetBSD.

Reviewed-by: Álvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Asif Naeem <anaeem.it@gmail.com>

src/interfaces/ecpg/test/expected/pgtypeslib-dt_test2.c

@@ -127,12 +127,9 @@ main(void)
 		{
 			for (j = 0; times[j]; j++)
 			{
-				int length = strlen(dates[i])
-						+ 1
-						+ strlen(times[j])
-						+ 1;
-				char* t = malloc(length);
-				sprintf(t, "%s %s", dates[i], times[j]);
+				char* t;
+				if (asprintf(&t, "%s %s", dates[i], times[j]) < 0)
+					abort();
 				ts1 = PGTYPEStimestamp_from_asc(t, NULL);
 				text = PGTYPEStimestamp_to_asc(ts1);
 				if (i != 19 || j != 3) /* timestamp as integer or double differ for this case */

src/interfaces/ecpg/test/pgtypeslib/dt_test2.pgc

@@ -92,12 +92,9 @@ main(void)
 		{
 			for (j = 0; times[j]; j++)
 			{
-				int length = strlen(dates[i])
-						+ 1
-						+ strlen(times[j])
-						+ 1;
-				char* t = malloc(length);
-				sprintf(t, "%s %s", dates[i], times[j]);
+				char* t;
+				if (asprintf(&t, "%s %s", dates[i], times[j]) < 0)
+					abort();
 				ts1 = PGTYPEStimestamp_from_asc(t, NULL);
 				text = PGTYPEStimestamp_to_asc(ts1);
 				if (i != 19 || j != 3) /* timestamp as integer or double differ for this case */

src/interfaces/libpq/fe-auth.c

@@ -420,7 +420,6 @@ pg_GSS_startup(PGconn *conn)
 {
 	OM_uint32	maj_stat,
 				min_stat;
-	int			maxlen;
 	gss_buffer_desc temp_gbuf;
 
 	if (!(conn->pghost && conn->pghost[0] != '\0'))
@@ -441,10 +440,14 @@ pg_GSS_startup(PGconn *conn)
 	 * Import service principal name so the proper ticket can be acquired by
 	 * the GSSAPI system.
 	 */
-	maxlen = NI_MAXHOST + strlen(conn->krbsrvname) + 2;
-	temp_gbuf.value = (char *) malloc(maxlen);
-	snprintf(temp_gbuf.value, maxlen, "%s@%s",
-			 conn->krbsrvname, conn->pghost);
+	if (asprintf((char **)&temp_gbuf.value, "%s@%s",
+				 conn->krbsrvname, conn->pghost) < 0)
+	{
+		printfPQExpBuffer(&conn->errorMessage,
+						  libpq_gettext("out of memory"));
+		return STATUS_ERROR;
+	}
+
 	temp_gbuf.length = strlen(temp_gbuf.value);
 
 	maj_stat = gss_import_name(&min_stat, &temp_gbuf,
@@ -656,13 +659,11 @@ pg_SSPI_startup(PGconn *conn, int use_negotiate)
 						  libpq_gettext("host name must be specified\n"));
 		return STATUS_ERROR;
 	}
-	conn->sspitarget = malloc(strlen(conn->krbsrvname) + strlen(conn->pghost) + 2);
-	if (!conn->sspitarget)
+	if (asprintf(&conn->sspitarget, "%s/%s", conn->krbsrvname, conn->pghost) < 0)
 	{
 		printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n"));
 		return STATUS_ERROR;
 	}
-	sprintf(conn->sspitarget, "%s/%s", conn->krbsrvname, conn->pghost);
 
 	/*
 	 * Indicate that we're in SSPI authentication mode to make sure that