Updating makefile

[syclik]

Submisison Checklist

• Run tests: ./runCmdStanTests.py src/test
• Declare copyright holder and open-source license: see below

Summary:

Fixes makefile.

Intended Effect:

This forces the LDLIBS variable to be used when building bin/stanc.

How to Verify:

Change make/local.

Side Effects:

None.

Documentation:

None. This should have already worked.

Reviewer Suggestions:

Anyone.

Copyright and Licensing

Please list the copyright holder for the work you are submitting (this will be you or your assignee, such as a university or company):

Columbia University

By submitting this pull request, the copyright holder is agreeing to license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)