prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Installing rclone leaves a go folder outside spack root
  Spack version: commit a45c4ef33de (if no change on relevant part, it is basically the head).
  OS distribution: Ubuntu server 18.04.
  
  After `spack install rclone`, there is a folder named go outside spack installation root as `~/go/` (the spack root is `~/spack/`). I have no idea about go lang, but it seems to be the go packages directory, denoted as `$GOPATH`.
  
  I wonder whether it is necessary to leave something outside spack root or should it be simple to move such GOPATH within spack root by hacking some repos (such as go or rclone).
  
  BTW, 
  ```bash
  module show go-1.11.5-gcc-7.4.0-gm
  --------------------------------------------------------------------------------------------------------------------------------
     /home/ubuntu/spack/share/spack/modules/linux-ubuntu18.04-x86_64/go-1.11.5-gcc-7.4.0-gm:
  --------------------------------------------------------------------------------------------------------------------------------
  whatis("The golang compiler and build environment ")
  prepend_path("PATH","/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/bin")
  prepend_path("LD_LIBRARY_PATH","/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/lib")
  prepend_path("LIBRARY_PATH","/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/lib")
  prepend_path("CMAKE_PREFIX_PATH","/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/")
  help([[The golang compiler and build environment
  ]])
  ```
  The auto generated module file for go by spack has no modification on `$GOPATH`.
  
  Correct me if I have any misunderstanding on go or its way of doing things, since literally I know nothing about it.
  
  </issue>
  <code>
  [start of var/spack/repos/builtin/packages/rclone/package.py]
  1 # Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
  2 # Spack Project Developers. See the top-level COPYRIGHT file for details.
  3 #
  4 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
  5 
  6 from spack import *
  7 
  8 
  9 class Rclone(Package):
  10     """Rclone is a command line program to sync files and directories
  11        to and from various cloud storage providers"""
  12 
  13     homepage = "http://rclone.org"
  14     url      = "https://github.com/ncw/rclone/releases/download/v1.43/rclone-v1.43.tar.gz"
  15 
  16     version('1.43', sha256='d30527b00cecb4e5e7188dddb78e5cec62d67cf2422dab82190db58512b5a4e3')
  17 
  18     depends_on("go", type='build')
  19 
  20     def install(self, spec, prefix):
  21         go('build')
  22         mkdirp(prefix.bin)
  23         install('rclone', prefix.bin)
  24
  [end of var/spack/repos/builtin/packages/rclone/package.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/var/spack/repos/builtin/packages/rclone/package.py b/var/spack/repos/builtin/packages/rclone/package.py
  --- a/var/spack/repos/builtin/packages/rclone/package.py
  +++ b/var/spack/repos/builtin/packages/rclone/package.py
  @@ -17,6 +17,10 @@
   
       depends_on("go", type='build')
   
  +    def setup_environment(self, spack_env, run_env):
  +        # Point GOPATH at the top of the staging dir for the build step.
  +        spack_env.prepend_path('GOPATH', self.stage.path)
  +
       def install(self, spec, prefix):
           go('build')
           mkdirp(prefix.bin)
  
verification_info: {"golden_diff": "diff --git a/var/spack/repos/builtin/packages/rclone/package.py b/var/spack/repos/builtin/packages/rclone/package.py\n--- a/var/spack/repos/builtin/packages/rclone/package.py\n+++ b/var/spack/repos/builtin/packages/rclone/package.py\n@@ -17,6 +17,10 @@\n \n     depends_on(\"go\", type='build')\n \n+    def setup_environment(self, spack_env, run_env):\n+        # Point GOPATH at the top of the staging dir for the build step.\n+        spack_env.prepend_path('GOPATH', self.stage.path)\n+\n     def install(self, spec, prefix):\n         go('build')\n         mkdirp(prefix.bin)\n", "issue": "Installing rclone leaves a go folder outside spack root\nSpack version: commit a45c4ef33de (if no change on relevant part, it is basically the head).\r\nOS distribution: Ubuntu server 18.04.\r\n\r\nAfter `spack install rclone`, there is a folder named go outside spack installation root as `~/go/` (the spack root is `~/spack/`). I have no idea about go lang, but it seems to be the go packages directory, denoted as `$GOPATH`.\r\n\r\nI wonder whether it is necessary to leave something outside spack root or should it be simple to move such GOPATH within spack root by hacking some repos (such as go or rclone).\r\n\r\nBTW, \r\n```bash\r\nmodule show go-1.11.5-gcc-7.4.0-gm\r\n--------------------------------------------------------------------------------------------------------------------------------\r\n   /home/ubuntu/spack/share/spack/modules/linux-ubuntu18.04-x86_64/go-1.11.5-gcc-7.4.0-gm:\r\n--------------------------------------------------------------------------------------------------------------------------------\r\nwhatis(\"The golang compiler and build environment \")\r\nprepend_path(\"PATH\",\"/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/bin\")\r\nprepend_path(\"LD_LIBRARY_PATH\",\"/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/lib\")\r\nprepend_path(\"LIBRARY_PATH\",\"/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/lib\")\r\nprepend_path(\"CMAKE_PREFIX_PATH\",\"/home/ubuntu/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/go-1.11.5-gmcvqdwr6az4hxbicr375if5fttk6sna/\")\r\nhelp([[The golang compiler and build environment\r\n]])\r\n```\r\nThe auto generated module file for go by spack has no modification on `$GOPATH`.\r\n\r\nCorrect me if I have any misunderstanding on go or its way of doing things, since literally I know nothing about it.\n", "before_files": [{"content": "# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other\n# Spack Project Developers. See the top-level COPYRIGHT file for details.\n#\n# SPDX-License-Identifier: (Apache-2.0 OR MIT)\n\nfrom spack import *\n\n\nclass Rclone(Package):\n    \"\"\"Rclone is a command line program to sync files and directories\n       to and from various cloud storage providers\"\"\"\n\n    homepage = \"http://rclone.org\"\n    url      = \"https://github.com/ncw/rclone/releases/download/v1.43/rclone-v1.43.tar.gz\"\n\n    version('1.43', sha256='d30527b00cecb4e5e7188dddb78e5cec62d67cf2422dab82190db58512b5a4e3')\n\n    depends_on(\"go\", type='build')\n\n    def install(self, spec, prefix):\n        go('build')\n        mkdirp(prefix.bin)\n        install('rclone', prefix.bin)\n", "path": "var/spack/repos/builtin/packages/rclone/package.py"}]}