include guards of ls-mat4.h and ov-type-conv.h

[John W. Eaton]

On 12-Jun-2009, NODA, Kai wrote:

| Greetings,
| 
| Here is a patch which fixes malfunctioning and lack of include guards.
| I noticed these while testing my Bash script which feeds
| #include <foo.h>
| #include <foo.h>
| to cpp and does wc -l on the output.
| If the number of lines is twice as large as the case of single #include <foo.h>,
| there should be a bug around include guard of foo.h.

I checked in this change, attributed to you.

Thanks,

jwe