libcurl-the-guide

[1] = HTTP PUT without knowing the size prior to transfer is indeed possible,
      but libcurl does not support the chunked transfers on uploading that is
      necessary for this feature to work. We'd gratefully appreciate patches
      that bring this functionality...

[2] = This happens on Windows machines when libcurl is built and used as a
      DLL. However, you can still do this on Windows if you link with a static
      library.

[3] = The curl-config tool is generated at build-time (on unix-like systems)
      and should be installed with the 'make install' or similar instruction
      that installs the library, header files, man pages etc.