#925 XLC syntax warning

[Jeff Hammond]

XLC is rather strict about syntax:

[ 18%] Building C object src/formats/libinchi/CMakeFiles/inchi.dir/inchi_dll.o
[ 18%] Building C object src/formats/libinchi/CMakeFiles/inchi.dir/inchi_dll_a.o
"/home/jhammond/OPENBABEL/openbabel/src/formats/libinchi/ikey_dll.c", line 265.10: 1506-342 (W) "/*" detected in comment.

Merge in the following to fix this issue.

https://github.com/jeffhammond/openbabel/commit/16fa16a1199927712c9bdc4133ada50087e84f5d

Thanks,

Jeff