An Autotools developer creates portable build systems for open-source software. They utilize GNU Autotools, a suite of programming tools designed to assist in making source code packages portable to many Unix-like systems. They use tools like Autoconf, Automake, and Libtool to generate makefiles and configure scripts. Their responsibilities include writing and maintaining build scripts, identifying and fixing portability issues, and streamlining build processes. Additionally, they ensure that software can be compiled, built, and installed on different hardware platforms and operating systems. Their work is crucial in facilitating the distribution and installation of open-source software.