also check for .so without version extension

[smoe]

Debian bookworm and later do not ship the freeglut3 library any more that provided the versioned symlink libglut.so.3 for the libglut.so.3.12.0 library, but there is libglut.so , still, and libglut.so.3.12.

$ ls -l /usr/lib/x86_64-linux-gnu/glut
-rw-r--r-- 1 root root 654216 5. Nov 21:59 /usr/lib/x86_64-linux-gnu/libglut.a
lrwxrwxrwx 1 root root 15 5. Nov 21:59 /usr/lib/x86_64-linux-gnu/libglut.so -> libglut.so.3.12
lrwxrwxrwx 1 root root 17 5. Nov 21:59 /usr/lib/x86_64-linux-gnu/libglut.so.3.12 -> libglut.so.3.12.0
-rw-r--r-- 1 root root 356016 5. Nov 21:59 /usr/lib/x86_64-linux-gnu/libglut.so.3.12.0

Several LinuxCNC issues/PRs are affected by this little omission, see LinuxCNC/linuxcnc#2259 and LinuxCNC/linuxcnc#1599. I tested this change locally and it worked for me. To test this run,

#!/usr/bin/python3
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
glutInit()

on Debian bookworm or later. Please also see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1029936 and likely also https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=512225.

[smoe]

Hm. Ping? The description reads a bit wild, admittedly, but the problem that neither libglut.so or libglut.so.3.12 are found and libglut.so.3 is gone in Debian bookworm is a real one. This patch helps to find libglut.so and thus solves this problem.