[C++] cmake script assumes that double-conversion installs static libs

[asfimport]

This line: https://github.com/apache/arrow/blob/master/cpp/cmake_modules/ThirdpartyToolchain.cmake#L580

The double-conversion project can alternatively build shared libraries, when BUILD_SHARED_LIBS=ON is used.

You should only use libraries that double-conversion cmake script provides, which is in the double-conversion_LIBRARIES variable.

Reporter: Yuri / @yurivict
Assignee: Uwe Korn / @xhochy

Related issues:

• [C++] Rework CMake third-party logic (is a child of)

Externally tracked issue: #3672

_{Note: This issue was originally created as ARROW-4608. Please see the migration documentation for further details.}

[asfimport]

Francois Saint-Jacques / @fsaintjacques:
I suspect that this was resolved in ARROW-4611, see https://github.com/apache/arrow/blob/master/cpp/cmake_modules/FindDoubleConversion.cmake#L39 .

[asfimport]

Uwe Korn / @xhochy:
Yes, this is fixed. We now use what is provided and preferred.