Allow DOS-style line endings in ~/.pgpass files.

On Windows, libc will mask \r\n line endings for us, since we read the
password file in text mode.  But that doesn't happen on Unix.  People
who share password files across both systems might have \r\n line endings
in a file they use on Unix, so as a convenience, ignore trailing \r.
Per gripe from Josh Berkus.

In passing, put the existing check for empty line somewhere where it's
actually useful, ie after stripping the newline not before.

Vik Fearing, adjusted a bit by me

Discussion: <0de37763-5843-b2cc-855e-5d0e5df25807@agliodbs.com>

src/interfaces/libpq/fe-connect.c

@@ -6026,18 +6026,26 @@ PasswordFromFile(char *hostname, char *port, char *dbname, char *username)
 			break;
 
 		len = strlen(buf);
-		if (len == 0)
-			continue;
 
 		/* Remove trailing newline */
-		if (buf[len - 1] == '\n')
-			buf[len - 1] = 0;
+		if (len > 0 && buf[len - 1] == '\n')
+		{
+			buf[--len] = '\0';
+			/* Handle DOS-style line endings, too, even when not on Windows */
+			if (len > 0 && buf[len - 1] == '\r')
+				buf[--len] = '\0';
+		}
+
+		if (len == 0)
+			continue;
 
 		if ((t = pwdfMatchesString(t, hostname)) == NULL ||
 			(t = pwdfMatchesString(t, port)) == NULL ||
 			(t = pwdfMatchesString(t, dbname)) == NULL ||
 			(t = pwdfMatchesString(t, username)) == NULL)
 			continue;
+
+		/* Found a match. */
 		ret = strdup(t);
 		fclose(fp);