minor fix for LD_LIBRARY_PATH setuid detection.

[Christos Zoulas]

For BSD it is more appropriate to (Greg feel free to commit this since I can't):

diff -r d6e9dd8952b4 src/os/bsd/launcher/java_md.c
--- a/src/os/bsd/launcher/java_md.c     Tue Nov 17 08:32:33 2009 -0500
+++ b/src/os/bsd/launcher/java_md.c     Tue Nov 24 15:20:02 2009 -0500
@@ -479,7 +479,7 @@
        * return from the function now.  Getting the right libraries to
        * be found must be handled through other mechanisms.
        */
-      if((getgid() != getegid()) || (getuid() != geteuid()) ) {
+      if(issetugid()) {
         return;
       }
 #endif

but really the way that the infinite loop of re-execing the launcher
when LD_LIBRARY_PATH is not set, is a horrible hack that breaks in
many different ways. The code is similar for linux, and it does
not work correctly there either, because __libc_enable_secure (the
variable in the dynamic linker that determines if the binary is
going to be run in secure mode), is also set when the binary has
capabilities, and the java code ignores that. I think we need
something more robust to prevent this infinite loop, such as setting
a different environment variable to indicate that we tried to exec
already, or pass a different command line argument. Just depending
on LD_LIBRARY_PATH being set is too fragile.

christos