Make get_my_path() safer

Adds maxLen parameter to get_my_path().
Some small cosmetic fixes.
diff --git a/adb/adb.h b/adb/adb.h
index b958682..a148019 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -236,7 +236,7 @@
 void handle_packet(apacket *p, atransport *t);
 void send_packet(apacket *p, atransport *t);
 
-void get_my_path(char s[PATH_MAX]);
+void get_my_path(char *s, size_t maxLen);
 int launch_server();
 int adb_main(int is_daemon);