* [CONTRIB][CC] Enhance cc.cross_compiler

- Enhance cc.cross_compiler to take str argument.
- Remove cc.build_create_shared_func as it is dupilicated with cross_compiler
- Add examples to cc.cross_compiler

* address review comments

* Revert compile_cmd kwarg name change

* Fix binutil tests

* uTVM interfaces (#14)

* some minor interface changes

* implemented HostLowLevelDevice

* added MicroDeviceAPI

* implemented micro_common and added Python interfaces

* current status, semi implemented micro session

* added micro_common implementation and python interfaces (#18)

* added micro_common implementation and python interfaces (#18)

* current status, semi implemented

* host test working

* updated interfaces for MicroSession arguments allocation

* make somewhat lint compatible

* fix based on comments

* added rounding macro

* fix minor bug

* improvements based on comments

* Clean up `binutil.py` and make Python-3-compatible

* Change argument allocation design

* Address feedback and lint errors

* Improve binutil tests

* Simplify allocator (per @tqchen's suggestions)

* Doc/style fixes

* farts

* mcgee

* rodata section werks

(and so does `test_runtime_micro_workspace.py`)

* simple graph runtime werk

* TEMP

* ResNet works, yo

* First round of cleanup

* More cleanup

* runs a dyson over the code

* Another pass

* Fix `make lint` issues

* ready to pr... probably

* final

* Undo change

* Fix rebase resolution

* Minor fixes

* Undo changes to C codegen tests

* Add `obj_path` in `create_micro_lib`

* TEMP

* Address feedback

* Add missing TODO

* Partially address feedback

* Fix headers

* Switch to enum class for `SectionKind`

* Add missing ASF header

* Fix lint

* Fix lint again

* Fix lint

* Kill lint warnings

* Address feedback

* Change Python interface to MicroTVM

All interaction with the device is now through `Session` objects, which
are used through Python's `with` blocks.

* Reorder LowLevelDevice interface

* Store shared ptr to session in all alloced objects

* Move helper functions out of `tvm.micro`

* Switch static char arr to vector

* Improve general infra and code quality

Does not yet address all of tqchen's feedback

* Forgot a rename

* Fix lint

* Add ASF header

* Fix lint

* Partially address MarisaKirisame's feedback

* Lint

* Expose `MicroSession` as a node to Python

* Revert to using `Session` constructor

* Fix compiler error

* (Maybe) fix CI error

* Debugging

* Remove

* Quell lint

* Switch to stack-based session contexts

* Make uTVM less intrusive to host codegen

And use SSA for operands of generated ternary operators

* Inline UTVMArgs into UTVMTask struct

* Remove `HostLowLevelDevice` header

* Remove `BaseAddr` class

* Address feedback

* Add "utvm" prefix to global vars in runtime

* Fix lint

* Fix CI

* Fix `test_binutil.py`

* Fix submodules

* Remove ResNet tests

* Make `test_binutil.py` work with nose

* Fix CI

* I swear this actually fixes the binutil tests

* lint

* lint

* Add fcompile-compatible cross-compile func

* Add docs for uTVM runtime files

* Move pointer patching into `MicroSession`

* Fix lint

* First attempt at unifying cross-compile APIs

* Fix lint

* Rename `cross_compile` back to `cc`

* Address feedback

* Remove commented code

* Lint

* Figure out failing function

* Remove debugging code

* Change "micro_dev" target to "micro"

* Add checks in tests for whether uTVM is enabled

* Add TODO for 32-bit support

* Rename more "micro_dev" to "micro"

* Undo rename

We already have `tvm.micro` as a namespace.  Can't have it as a method
as well.

* Fix failing CI

Thanks to @tqchen for finding this bug.  Emitting ternary operators for
`min` and `max` causes concurrency bugs in CUDA, so we're moving the
ternary op emissions from `CodeGenC` to `CodeGenCHost`.

* Address feedback

* Fix lint

* [HEADER] ASF header dir=include

* [HEADER] ASF Header dir=src

* [HEADER] ASF Header -dir=python

* [HEADER] ASF header dir=topi

* [HEADER] ASF Header dir=nnvm

* [HEADER] ASF Header -dir=tutorials

* [HEADER] ASF Header dir=tests

* [HEADER] ASF Header -dir=docker

* fix whitespace

* [HEADER] ASF Header -dir=jvm

* [HEADER] ASF Header -dir=web

* [HEADER] ASF Header --dir=apps

* [HEADER] ASF Header --dir=vta

* [HEADER] ASF Header -dir=go

* temp

* [HEADER] ASF Header --dir=rust

* [HEADER] Add ASF Header --dir=cmake

* [HEADER] ASF Header --dir=docs

* [HEADER] Header for Jenkinsfile

* [HEADER] ASF Header to toml and md

* [HEADER] ASF Header to gradle

* Finalize rat cleanup

* Fix permission

* Fix java test

* temporary remove nnvm onnx test

* use LLVM linker

* error message improved in case of filenotfound

* linting error fixed

* Implement C code generation with tests

* Code cleanup

* Implement C code generation with tests

* Code cleanup

* tabs to spaces

* make lint compliant

* update export_library and reserve unique C keywords

* move ReserveKeywordsAsUnique to codegen_c

* some documentation and code cleanup

* use tvm.contrib.util for tempdir in testcases

* Better error message handling for contrib

* fix lint

* fix testcase

* fix test

The type of parameter options should be a str list.

* add friendly tips when not found cl and link

* fix lint

* [RUNTIME] Add System Lib

* lint

* lint

* fix compile

* [CODEGEN/RUNTIME] Metal support, runtime improvement.

* Fix case when no device is available

* [OP/LANG] Support Extern Call, more regression tests

* [TEST] Include pylintrc