MFH: r405098

Fix linking after r404875.

There was a typo in the line setting LDFLAGS: we need -L/some/dir, not
/some/dir.

From the logs:

/usr/local/lib: file not recognized: Is a directory
c++: error: linker command failed with exit code 1 (use -v to see invocation)

Thanks to antoine for raising the issue, and sorry for the brain fart.