Switch to a preconfigured Clang for k8 and armv7

This one reuses more of Bazel's builtin features to remain up to date
more easily, and it's easier to expand support for more platforms. This
also takes care of upgrading to a newer Clang.

This will require updating to raspios bullseye on the Raspberry Pis.
This also renames armhf-debian to armv7 to match the broader Bazel
ecosystem's name for this architecture.

Change-Id: I3e2a4f4efea43e76314ca34a9293c7b4b45edd2c
Signed-off-by: Brian Silverman <bsilver16834@gmail.com>
diff --git a/debian/download_packages.py b/debian/download_packages.py
index 6331102..e3bb845 100755
--- a/debian/download_packages.py
+++ b/debian/download_packages.py
@@ -9,7 +9,9 @@
 import hashlib
 
 def get_deps(package):
-  out = subprocess.check_output(["apt-rdepends", package])
+  env = dict(os.environ)
+  del env['LD_LIBRARY_PATH']
+  out = subprocess.check_output(["apt-rdepends", package], env=env)
   deps = out.splitlines()
   return set([dep for dep in deps if not dep.startswith(b" ")])
 
@@ -50,6 +52,12 @@
     if package == b'libopencl1':
       yield b'ocl-icd-libopencl1'
       continue
+    if package == b'libgcc1':
+      yield b'libgcc-s1'
+      continue
+    if package == b'libopencl-1.2-1':
+      yield b'ocl-icd-libopencl1'
+      continue
     if package == b'libblas.so.3':
       yield b'libblas3'
       continue
@@ -61,7 +69,9 @@
   deps -= exclude_deps
   force_include_deps = get_all_deps(force_includes)
   deps |= force_include_deps
-  subprocess.check_call([b"apt-get", b"download"] + list(map_virtual_packages(deps)))
+  env = dict(os.environ)
+  del env['LD_LIBRARY_PATH']
+  subprocess.check_call([b"apt-get", b"download"] + list(map_virtual_packages(deps)), env=env)
 
 def fixup_files():
   # Gotta remove those pesky epoch numbers in the file names. Bazel doesn't