[fortran, doc] Fix doc for LOG intrinsic

[Tobias Burnus]

Am 12.03.2011 10:52, schrieb FX:
> The attached patch clarifies the documentation of the LOG intrinsic by stating explicitly that it's the natural log function.
>
> Tested with "make info html pdf", OK to commit to trun

I am mostly OK, however:

function
-@cindex logarithmic
+@cindex base 10 logarithm function

I think even when looking for the decadic logarithm (common logarithm), I would look under "L" for logarithm and not under "B" for "base". How about "logarithm function with base 10"? If you want, you could could also add, e.g., common/decadic logarithm to the index.

Tobias