use abspath

[terasakisatoshi]

resolve #635

[codecov]

Codecov Report

Merging #636 (497531e) into master (1116f4d) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #636   +/-   ##
=======================================
  Coverage   95.41%   95.41%           
=======================================
  Files           2        2           
  Lines         458      458           
=======================================
  Hits          437      437           
  Misses         21       21           

Impacted Files	Coverage Δ
src/PackageCompiler.jl	95.90% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1116f4d...497531e. Read the comment docs.