meson install does not install executables (no bin dir, gap_fit missing)

[stenczelt]

Problem

Running meson install does not produce a bin/ directory — no executables e.g. gap_fit are installed to the prefix.

This is the meson-build equivalent of #293.

Root cause

None of the executable() calls in src/Programs/meson.build have install: true. In Meson, executables must be explicitly marked for installation; without it they are built but never installed. The shared libraries (libAtoms, Potentials, Utils, GAP) already have install: true and are correctly installed.

Steps to reproduce

meson setup builddir -Dgap=true -Dmpi=false
meson configure builddir --prefix /path/to/install
meson compile -C builddir -j 8
meson install -C builddir
# Result: no bin/ directory at prefix, only lib/

Fix

Add install: true to all executable() calls in src/Programs/meson.build:

executable('gap_fit', '../GAP/gap_fit.F90',
  link_with: link_quip + [gap_fit_lib],
  dependencies: [blas_dep, mpi_dep],
  override_options: ['b_lundef=false'],
  install: true,   # <-- add this
)

Same applies to quip, the standard programs loop, and quip_wrapper_simple_example_C.