Wrong return value of which on Win10 for stdlib functions

[bkamins]

On current build of Julia 1.0 when you use where (or any other function that uses source location) looking up a definition of functions that are shipped with Julia in stdlib returns a wrong path (presumably a path to a file on a machine that was used to build system image that is used). Examples:

julia> which(rand, ())
rand() in Random at C:\cygwin\home\Administrator\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v0.7\Random\src\Random.jl:222


julia> using Pkg

julia> which(Pkg.add, (String,))
add(args...) in Pkg.API at C:\cygwin\home\Administrator\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v0.7\Pkg\src\API.jl:63

This causes commands like @edit rand() fail.

Locations of functions from Base are returned correctly, e.g.:

julia> which(pwd, ())
pwd() in Base.Filesystem at file.jl:51

julia> which(sin, (Float64,))
sin(x::T) where T<:Union{Float32, Float64} in Base.Math at special/trig.jl:30

[fredrikekre]

#28052