Found the following significant warnings:
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/../optimization/optimization_solve_qp_using_smo.h:630:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/../optimization/optimization_solve_qp_using_smo.h:910:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/../optimization/optimization_solve_qp_using_smo.h:911:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/../optimization/optimization_solve_qp_using_smo.h:913:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/../optimization/optimization_solve_qp_using_smo.h:914:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/lda.h:154:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_keypoint/../statistics/lda.h:155:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/../optimization/optimization_solve_qp_using_smo.h:630:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/../optimization/optimization_solve_qp_using_smo.h:910:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/../optimization/optimization_solve_qp_using_smo.h:911:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/../optimization/optimization_solve_qp_using_smo.h:913:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/../optimization/optimization_solve_qp_using_smo.h:914:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/lda.h:154:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/../statistics/lda.h:155:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/image_pyramid.h:1167:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/image_pyramid.h:1168:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/image_pyramid.h:1204:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/image_pyramid.h:1223:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/interpolation.h:2123:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
  ../inst/dlib-19.20/dlib/image_transforms/interpolation.h:2124:9: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
See ‘/data/gannet/ripley/R/packages/tests-clang/image.dlib.Rcheck/00install.out’ for details.
* used C++ compiler: ‘clang version 18.1.8’