Support LLVM trunk & building clang from git
Make Julia work on 10.9
Merge branch 'kf/osx1092' into kf/llvm34
Add flag to build LLVM with address sanitizer
Merge branch 'kf/llvm34' into kf/asan

Conflicts:
	Make.inc
	deps/Makefile
Add SANITIZE option
Fix eigvals for integer matrices. Define copy! and similar methods for Symmetric and Hermitian matrices.
remove _MISSING value in dict. closes #4802
document scope of keyword and optional argument default values. closes #4795
fix #4801, keyword arg in constructor on first call
fix some of the issues in #4807, arrays of Complex{T<:Real}
make gcdx type-stable & 20x faster, fix invmod to work with negative arguments, use GMP for BigInt invmod
improve matmul result type. closes #4807, closes #4796
make gcd and lcm positive (fix #4810)
update gcd/lcm/gcdx docs
ensure consistent results for gcdx(0,0) with BigInt
bugfix for lcm(0,0), add test coverage of gcd-related functions
fix performance bug in assert

also fix round-trip value<->expression conversion of `nothing`

in codegen for `quote`, avoid generating jl_copy_ast calls for atoms
domain error for negative powers in BigInt powermod
Merge pull request #4811 from stevengj/invmod

fix gcd & lcm sign and optimize gcdx and invmod