several projects in lib64 on CentOS

[smanders]

see related issues:

• ceres library in lib64 on CentOS https://github.com/smanders/externpro/issues/206
• make use of CMAKEINSTALL[BIN|LIB]DIR https://github.com/smanders/externpro/issues/37

[smanders]

projects that

include(GNUInstallDirs)

will have to deal with this issue

• c-ares
• libssh2 (1.5.0 and 1.9.0)
• curl (7.42.1 and 7.66.0)

[smanders]

completed with commit to dev branch referenced above