Fix Catch2 include path. GitHub issue #379.

Disable POSIX signals reception in thread before creating pool
threads. GitHub issue #385 and follow up issue #390.

Fix compilation with NVCC in CUDA mode. GitHub issue #375.

Fix compilation with Visual Studio in C++17 mode. GitHub issue #401.

Allow disabling implicit initialization through configure script option
--disable-implicit-initialization, or CMake build option
LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION. (MaksymB)

Remove android directory with obsolete Android support. GitHub
issue #283.

Link with libatomic when necessary. (Fabrice Fontaine)