Working with GNU Autoconf

GNU Autoconf, or simply the GNU build system, is a suite of build tools designed to assist in making source code packages portable across multiple Unix-like systems.

Autoconf contains multiple build-related tools and generally acts as a Makefile generator. Makefile templates are processed in the configure build step using environment information and configuration options specified by the user.

The Autoconf system is quite complex and there exists some controversy about its usage in modern projects. For some projects it may be too old, too complex, and too directed towards Unix-like systems compared to the cost of other platforms. But for OpenJDK, the highly cross-platform project that already heavily relies on Unix-like tools, autotool adoption for the configure build step is well justified.

The Autoconf system uses GNU make for the actual build step, but in contrast to the make tool, the whole Autoconf package is less portable, and a particular build setup may have...