ARROW-6462: [C++] Fix build error on CentOS 6 x86_64 with bundled double-conversion
ARROW-6462: [C++] Fix build error on CentOS 6 x86_64 with bundled double-conversion

Because ${prefix}/lib64 is used on CentOS 6 x86_64.

Closes #5289 from kou/cpp-double-conversion-bundled-centos-6 and squashes the following commits:

a6b5fdfde <Sutou Kouhei>  Fix build error on CentOS 6 x86_64 with bundled double-conversion

Authored-by: Sutou Kouhei <73218711cdd5d5c30ac66da3cc4d9d9204caf34b@clear-code.com>
Signed-off-by: Krisztián Szűcs <6bab32dc957a05a87930e779f272342e159326fa@gmail.com>

kou/arrow,cpcloud/arrow,xhochy/arrow,icexelloss/arrow,cpcloud/arrow,laurentgo/arrow,wesm/arrow,icexelloss/arrow,renesugar/arrow,kou/arrow,laurentgo/arrow,apache/arrow,cpcloud/arrow,xhochy/arrow,wesm/arrow,kou/arrow,kou/arrow,cpcloud/arrow,icexelloss/arrow,wesm/arrow,laurentgo/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow,kou/arrow,apache/arrow,laurentgo/arrow,cpcloud/arrow,cpcloud/arrow,apache/arrow,xhochy/arrow,kou/arrow,cpcloud/arrow,cpcloud/arrow,wesm/arrow,apache/arrow,renesugar/arrow,laurentgo/arrow,kou/arrow,renesugar/arrow,apache/arrow,cpcloud/arrow,wesm/arrow,xhochy/arrow,cpcloud/arrow,laurentgo/arrow,icexelloss/arrow,cpcloud/arrow,renesugar/arrow,xhochy/arrow,wesm/arrow,icexelloss/arrow,cpcloud/arrow,renesugar/arrow,renesugar/arrow,apache/arrow,renesugar/arrow,icexelloss/arrow,apache/arrow,cpcloud/arrow,cpcloud/arrow,kou/arrow,laurentgo/arrow,icexelloss/arrow,kou/arrow,icexelloss/arrow,apache/arrow,icexelloss/arrow,laurentgo/arrow,xhochy/arrow,apache/arrow,renesugar/arrow,apache/arrow,kou/arrow,renesugar/arrow,laurentgo/arrow,laurentgo/arrow,icexelloss/arrow,icexelloss/arrow,renesugar/arrow,apache/arrow,renesugar/arrow,xhochy/arrow,xhochy/arrow,xhochy/arrow,laurentgo/arrow,laurentgo/arrow,kou/arrow,xhochy/arrow,kou/arrow,apache/arrow,wesm/arrow,wesm/arrow,renesugar/arrow,wesm/arrow,apache/arrow,wesm/arrow,renesugar/arrow,icexelloss/arrow,renesugar/arrow,xhochy/arrow,kou/arrow,wesm/arrow,icexelloss/arrow,xhochy/arrow,icexelloss/arrow,kou/arrow,xhochy/arrow,xhochy/arrow,laurentgo/arrow,renesugar/arrow,apache/arrow,wesm/arrow,wesm/arrow,xhochy/arrow