By default the cmake files are installed to "<prefix>/lib/cmake/cppformat".
This can now be customized using the `FMT_CMAKE_DIR` cache variable.
Valid paths are documented in the cmake manual [1].

e.g., install the cmake files to "<prefix>/share/cmake/cppformat"
```
cmake -DFMT_CMAKE_DIR=share/cmake/cppformat <path-to-source>
```

Tip: Try `make package` to examine the result.

[1] https://cmake.org/cmake/help/v3.0/command/find_package.html

Error:
expected unqualified-id before '(' token
 int fmt::BufferedFile::fileno() const {

This is an issue with Android NDK and mingw32.

https://github.com/Gachapen/cppformat/commit/c2ffa146841535080a3483471fd9eec77c119c36

to version https://github.com/cppformat/cppformat/commit/7ee287d3d9e340737f3ad66292e7bc60a53b3053

Silence some performance warnings in Visual Studio

Older Visual Studio versions are not shipped with stdint.h

in custom stream buffer implementation:

* basic_formatbuf -> internal::FormatBuf
* remove unused Traits template argument