Merge branch 'mplegendre-multi_pkgsrc_roots' into develop

- This moves var/spack/packages to var/spack/repos/builtin/packages.

- Packages that did not exist in the source branch, or were changed in
  develop, were moved into var/spack/repos/builtin/packages as part of
  the integration.

Conflicts:
	lib/spack/spack/test/unit_install.py
	var/spack/repos/builtin/packages/clang/package.py

var/spack/repos/builtin/packages/julia/gc.patch

@@ -0,0 +1,11 @@
+--- julia/src/gc.c
++++ julia/src/gc.c
+@@ -162,7 +162,7 @@
+ // A region is contiguous storage for up to REGION_PG_COUNT naturally aligned GC_PAGE_SZ pages
+ // It uses a very naive allocator (see malloc_page & free_page)
+ #if defined(_P64) && !defined(_COMPILER_MICROSOFT_)
+-#define REGION_PG_COUNT 16*8*4096 // 8G because virtual memory is cheap
++#define REGION_PG_COUNT 8*4096 // 512M
+ #else
+ #define REGION_PG_COUNT 8*4096 // 512M
+ #endif

var/spack/repos/builtin/packages/julia/package.py

@@ -0,0 +1,70 @@
+from spack import *
+import os
+
+class Julia(Package):
+    """The Julia Language: A fresh approach to technical computing"""
+    homepage = "http://julialang.org"
+    url      = "http://github.com/JuliaLang/julia/releases/download/v0.4.2/julia-0.4.2.tar.gz"
+
+    version('0.4.3', '7b9f096798fca4bef262a64674bc2b52')
+    version('0.4.2', 'ccfeb4f4090c8b31083f5e1ccb03eb06')
+
+    patch('gc.patch')
+
+    # Build-time dependencies
+    depends_on("cmake @2.8:")
+    # depends_on("awk")
+    # depends_on("m4")
+    # depends_on("pkg-config")
+    depends_on("python @2.6:2.9")
+
+    # I think that Julia requires the dependencies above, but it builds find (on
+    # my system) without these. We should enable them as necessary.
+
+    # Run-time dependencies
+    # depends_on("arpack")
+    # depends_on("fftw +float")
+    # depends_on("gmp")
+    # depends_on("mpfr")
+    # depends_on("pcre2")
+
+    # ARPACK: Requires BLAS and LAPACK; needs to use the same version as Julia.
+
+    # BLAS and LAPACK: Julia prefers 64-bit versions on 64-bit systems. OpenBLAS
+    # has an option for this; make it available as variant.
+
+    # FFTW: Something doesn't work when using a pre-installed FFTW library; need
+    # to investigate.
+
+    # GMP, MPFR: Something doesn't work when using a pre-installed FFTW library;
+    # need to investigate.
+
+    # LLVM: Julia works only with specific versions, and might require patches.
+    # Thus we let Julia install its own LLVM.
+
+    # Other possible dependencies:
+    # USE_SYSTEM_OPENLIBM=0
+    # USE_SYSTEM_OPENSPECFUN=0
+    # USE_SYSTEM_DSFMT=0
+    # USE_SYSTEM_SUITESPARSE=0
+    # USE_SYSTEM_UTF8PROC=0
+    # USE_SYSTEM_LIBGIT2=0
+
+    def install(self, spec, prefix):
+        # Explicitly setting CC, CXX, or FC breaks building libuv, one of
+        # Julia's dependencies. This might be a Darwin-specific problem. Given
+        # how Spack sets up compilers, Julia should still use Spack's compilers,
+        # even if we don't specify them explicitly.
+        options = [#"CC=cc",
+                   #"CXX=c++",
+                   #"FC=fc",
+                   #"USE_SYSTEM_ARPACK=1",
+                   #"USE_SYSTEM_FFTW=1",
+                   #"USE_SYSTEM_GMP=1",
+                   #"USE_SYSTEM_MPFR=1",
+                   #TODO "USE_SYSTEM_PCRE=1",
+                   "prefix=%s" % prefix]
+        with open('Make.user', 'w') as f:
+            f.write('\n'.join(options) + '\n')
+        make()
+        make("install")