ERROR: Failed to precompile PyCall

Hi,

I'm getting the following error:
```
ERROR: Failed to precompile PyCall to /Users/karel/.julia/lib/v0.5/PyCall.ji.
in compilecache(::String) at ./loading.jl:593
in require(::Symbol) at ./loading.jl:422
in require(::Symbol) at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib:?
```
I have the following info
```
Julia Version 0.5.0
Commit 3c9d753 (2016-09-19 18:14 UTC)
Platform Info:
System: Darwin (x86_64-apple-darwin13.4.0)
CPU: Intel(R) Core(TM) i5-2415M CPU @ 2.30GHz
WORD_SIZE: 64
uname: Darwin 14.5.0 Darwin Kernel Version 14.5.0: Sun Sep 25 22:07:15 PDT 2016; root:xnu-2782.50.9~1/RELEASE_X86_64 x86_64 i386
Memory: 8.0 GB (253.6953125 MB free)
Uptime: 841779.0 sec
Load Avg: 2.7802734375 2.693359375 2.69482421875
Intel(R) Core(TM) i5-2415M CPU @ 2.30GHz:
speed user nice sys idle irq
#1 2300 MHz 2143979 s 0 s 783761 s 2848735 s 0 s
#2 2300 MHz 629401 s 0 s 232240 s 4905198 s 0 s
#3 2300 MHz 2084304 s 0 s 670470 s 3012065 s 0 s
#4 2300 MHz 667471 s 0 s 240400 s 4858966 s 0 s

BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Sandybridge)
LAPACK: libopenblas64_
LIBM: libopenlibm
LLVM: libLLVM-3.7.1 (ORCJIT, sandybridge)
Environment:
TERM = xterm-256color
PATH = /Applications/Julia-0.5.app/Contents/Resources/julia/bin:/Applications/Julia-0.5.0.app/Contents/Resources/julia/bin/julia:/Applications/MATLAB_R2016a.app/bin:/Users/karel/anaconda/bin:/Applications/Julia-0.5.app/Contents/Resources/julia/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin:/Library/TeX/texbin
XPC_FLAGS = 0x0
HOME = /Users/karel
FONTCONFIG_PATH = /Applications/Julia-0.5.app/Contents/Resources/julia/etc/fonts

Package Directory: /Users/karel/.julia/v0.5
8 required packages:
- Atom 0.5.8
- DataFrames 0.8.5
- MAT 0.3.1
- MATLAB 0.5.0
- NPZ 0.2.0
- Plots 0.10.3
- PyCall 1.10.0
- PyPlot 2.3.1
62 additional packages:
- ASTInterpreter 0.0.4
- AbstractTrees 0.0.4
- ArgParse 0.4.0
- BinDeps 0.4.5
- Blink 0.5.1
- Blosc 0.1.7
- BufferedStreams 0.3.0
- COFF 0.0.2
- CRC 1.2.0
- CodeTools 0.4.3
- Codecs 0.2.0
- ColorTypes 0.3.2
- Colors 0.7.1
- Compat 0.16.2
- Conda 0.5.1
- DWARF 0.1.0
- DataArrays 0.3.12
- DataStructures 0.5.2
- ELF 0.1.0
- FileIO 0.3.0
- FixedPointNumbers 0.3.2
- FixedSizeArrays 0.2.5
- GZip 0.2.20
- Gallium 0.0.4
- HDF5 0.7.3
- Hiccup 0.1.1
- Homebrew 0.4.2
- HttpCommon 0.2.6
- HttpParser 0.2.0
- HttpServer 0.1.7
- Iterators 0.2.0
- JSON 0.8.2
- JuliaParser 0.7.4
- Juno 0.2.5
- LNR 0.0.2
- LaTeXStrings 0.2.0
- Lazy 0.11.5
- Libz 0.2.3
- MachO 0.0.4
- MacroTools 0.3.5
- MbedTLS 0.4.3
- Measures 0.0.3
- Media 0.2.5
- Mustache 0.1.3
- Mux 0.2.3
- ObjFileBase 0.0.4
- PlotThemes 0.1.1
- PlotUtils 0.3.0
- Reactive 0.3.7
- RecipesBase 0.1.0
- Reexport 0.0.3
- SHA 0.3.1
- Showoff 0.0.7
- SortingAlgorithms 0.1.0
- StatsBase 0.13.0
- StructIO 0.0.2
- TerminalUI 0.0.2
- TextWrap 0.1.6
- URIParser 0.1.8
- VT100 0.0.2
- WebSockets 0.2.1
- ZipFile 0.3.0
```
Any ideas?

The report identifies PyCall 1.10.0, Julia 0.5.0, and a macOS precompilation failure, but names no source file or test. Start by reproducing the PyCall load failure in that environment and obtain the complete precompilation error. Done means identifying a reproducible cause and confirming that PyCall precompiles and loads successfully.

Escrito por el modelo de indexación a partir del texto del issue.