Compile M_intrinsics, fman, and gtk-fortran packages with LFortran

This proposal aims to improve LFortran by compiling and validating real-world Fortran packages such as M_intrinsics, fman, and gtk-fortran. Instead of focusing on isolated features, it follows a compilation-driven approach to identify and resolve limitations across different stages of the compiler, including parsing, semantic analysis, code generation, and runtime support. Key issues such as incomplete I/O specifier handling, quadruple precision support, and array constructor transformations will be addressed. The project emphasizes iterative development, testing, and validation against reference compilers, with the goal of improving LFortran’s robustness, correctness, and support for complex, real-world applications.