partial support for out-of-tree builds of julia src
faster randn by separating out unlikely branch in a function

All credits to @ViralBShah (cf. #8941 and #9126).
This change probably allows better inlining.
SubArray: default to linear indexing when it's fast
fix bigfloat itrunc error
juliatypes.jl: implement exhaustive search over unions

currently this breaks unions in varargs

we also need to handle multiple lexical occurrences of the same Union, e.g.

U = Union(Int,Int8); (U, U, U)

since I'm replacing Unions based on object id. hopefully this fix can also
restore varargs, by recording multiple occurrences of the union in

(A, B, C) <: (Union(C,D)...)
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #9138 from simonbyrne/bigfloat-itrunc

fix bigfloat itrunc error
update BLAS.scal! to only accept DenseArray

real-scalar, complex-array now handled in dense.jl
correct return value for scale! on real-scalar, complex-array
Merge pull request #8904 from JuliaLang/jn/out_of_tree_build

partial support for out-of-tree builds of julia src
Merge pull request #9132 from JuliaLang/rf/randn-splitbranch

faster randn by separating out unlikely branch in a function
Use memset to fill! floating-point arrays as well
Merge pull request #9141 from nwh/blas-scal-cleanup

Blas scal cleanup
fix #9134, regression on uninitialized `let` variable
Remove randmtzig_randn and just have randn as the interface.
Perhaps we should do the same and have randexp, instead of randmtzig_exprnd.
Merge branch 'master' of github.com:JuliaLang/julia
fix #9134, regression on uninitialized `let` variable
Remove usage of randmtzig_randn in randn(array).
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #9142 from eschnett/float-fill

Use memset to fill! floating-point arrays as well