TST: test 3.4 on windows
BLD: bug in building json compiled code
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=h1) Report
> Merging [#15857](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/1b53d8864af0ed936f84d0935e2cc360dc9f8de7?src=pr&el=desc) will **increase** coverage by `0.18%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/15857/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #15857      +/-   ##
==========================================
+ Coverage   90.98%   91.17%   +0.18%     
==========================================
  Files         143      108      -35     
  Lines       49443    47584    -1859     
==========================================
- Hits        44985    43383    -1602     
+ Misses       4458     4201     -257
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.94% <ø> (+0.22%)` | :arrow_up: |
| #single | `40.81% <ø> (+0.04%)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/io/msgpack/exceptions.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2lvL21zZ3BhY2svZXhjZXB0aW9ucy5weQ==) | `77.27% <0%> (-6.07%)` | :arrow_down: |
| [pandas/core/index.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXgucHk=) | `95.42% <0%> (-4.58%)` | :arrow_down: |
| [pandas/computation/ops.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2NvbXB1dGF0aW9uL29wcy5weQ==) | `93.95% <0%> (-1.65%)` | :arrow_down: |
| [pandas/computation/api.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2NvbXB1dGF0aW9uL2FwaS5weQ==) | `98.92% <0%> (-1.08%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.23% <0%> (-0.43%)` | :arrow_down: |
| [pandas/types/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL3R5cGVzL2dlbmVyaWMucHk=) | | |
| [pandas/io/msgpack/\_version.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2lvL21zZ3BhY2svX3ZlcnNpb24ucHk=) | | |
| [pandas/core/sparse.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3BhcnNlLnB5) | | |
| [pandas/tseries/plotting.py](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvcGxvdHRpbmcucHk=) | | |
| ... and [69 more](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=tree-more) | |

------

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> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=footer). Last update [1b53d88...12c70a1](https://codecov.io/gh/pandas-dev/pandas/pull/15857?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).