compiling_swift_armv6_on_debianarmv7.md

• Link gcc and g++ to clang and clang++ respectively if necessary

• Move /bin/uname to /bin/uname.orig and override it with a /bin/uname script that calls /bin/uname.orig "$@" | sed 's/armv7l/armv6l/g'

• Force armv6l for build-impl-script instead of using python's platform.machine() that calls the uname syscall (setarch cannot be used since armv6 cannot be set...):

  diff --git a/utils/swift_build_support/swift_build_support/targets.py b/utils/swift_build_support/swift_build_support/targets.
  py
  index 2859677fac..b7d65c4f9a 100644
  --- a/utils/swift_build_support/swift_build_support/targets.py
  +++ b/utils/swift_build_support/swift_build_support/targets.py
  @@ -156,7 +156,7 @@ class StdlibDeploymentTarget(object):
           the recognized targets. Otherwise, throw a NotImplementedError.
           """
           system = platform.system()
  -        machine = platform.machine()
  +        machine = "armv6l" #platform.machine()
  
           if system == 'Linux':
               if machine == 'x86_64':