See #737

- matheval not needed
- fftw is already on by default

I tested by changing --print-prog-name to --print-prog-namex (not existing) so as to reproduce
the bug, and this seems to fix it so I merge it.

See #726

Update README.md fix typo

Fixed typo "recomment" -> "recommend"

Can be used for numeric comparisons in precompiler directives

Error is this one:
../maketools/makelinks.sh: line 24: echo: write error: Broken pipe

It's triggered by the comparison with a <(echo) file, since the comparison
might fail before echo completes. If this works I will backport it

minor improvements to OPES_METAD

See #524