Stop being a ☠️ (fix #900, ldiv! and dot pirates Base).

[pkofod]

I just define our own that falls back to LinearAlgebra's.

[codecov]

Codecov Report

Merging #916 (e1f7dae) into master (adc5b27) will increase coverage by 0.10%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##           master     #916      +/-   ##
==========================================
+ Coverage   83.59%   83.69%   +0.10%     
==========================================
  Files          43       43              
  Lines        3023     3024       +1     
==========================================
+ Hits         2527     2531       +4     
+ Misses        496      493       -3     

Impacted Files	Coverage Δ
src/Optim.jl	100.00% <ø> (ø)
src/multivariate/precon.jl	70.00% <83.33%> (+14.44%)	⬆️
src/multivariate/solvers/constrained/samin.jl	78.06% <0.00%> (+1.29%)	⬆️

---

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 adc5b27...e1f7dae. Read the comment docs.