;;; qemu.scm
;; I'm on debian, with guix installed via curl. My guix version:
;;
;; $ guix --version
;; guix (GNU Guix) 1.4.0
;; Copyright (C) 2022 the Guix authors
;; License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
;; This is free software: you are free to change and redistribute it.
;; There is NO WARRANTY, to the extent permitted by law.
;;
;; I run build the file like so:
;;
;; $ time guix package -v3 -K -f qemu.scm
;; /home/stites/dev/guix/mnt-reform-nonguix/qemu.scm:45:18: error: (else (quote ())): bad use of 'else' syntactic keyword
;; guix package -v3 -K -f qemu.scm  0.87s user 0.11s system 132% cpu 0.741 total

(define-module (qemu)
  #:use-module (gnu packages)
  #:use-module (gnu packages virtualization))

;; the rest (minus the last line) of this is c/p'd from qemu-minimal with a :%s/qemu-minimal/myqemu/g applied.

(define-public myqemu
  ;; QEMU without GUI support, only supporting the host's architecture
  (package/inherit qemu
    (name "myqemu")
    (outputs '("out" "doc"))
    (synopsis
     "Machine emulator and virtualizer (without GUI) for the host architecture")
    (arguments
     (substitute-keyword-arguments (package-arguments qemu)
       ((#:configure-flags configure-flags #~'())
        ;; Restrict to the host's architecture.
        (let* ((system (or (%current-target-system)
                           (%current-system)))
               (target-list-arg
                (match system
                  ((? (cut string-prefix? "i686" <>))
                   "--target-list=i386-softmmu")
                  ((? (cut string-prefix? "x86_64" <>))
                   "--target-list=i386-softmmu,x86_64-softmmu")
                  ((? (cut string-prefix? "mips64" <>))
                   (string-append "--target-list=mips-softmmu,mipsel-softmmu,"
                                  "mips64-softmmu,mips64el-softmmu"))
                  ((? (cut string-prefix? "mips" <>))
                   "--target-list=mips-softmmu,mipsel-softmmu")
                  ((? (cut string-prefix? "aarch64" <>))
                   "--target-list=arm-softmmu,aarch64-softmmu")
                  ((? (cut string-prefix? "arm" <>))
                   "--target-list=arm-softmmu")
                  ((? (cut string-prefix? "alpha" <>))
                   "--target-list=alpha-softmmu")
                  ((? (cut string-prefix? "powerpc64" <>))
                   "--target-list=ppc-softmmu,ppc64-softmmu")
                  ((? (cut string-prefix? "powerpc" <>))
                   "--target-list=ppc-softmmu")
                  ((? (cut string-prefix? "s390" <>))
                   "--target-list=s390x-softmmu")
                  ((? (cut string-prefix? "riscv" <>))
                   "--target-list=riscv32-softmmu,riscv64-softmmu")
                  (else       ; An empty list actually builds all the targets.
                   '()))))
          #~(cons #$target-list-arg #$configure-flags)))
       ((#:phases phases)
        #~(modify-phases #$phases
            (delete 'configure-user-static)
            (delete 'build-user-static)
            (delete 'install-user-static)))))

    ;; Remove dependencies on optional libraries, notably GUI libraries.
    (native-inputs (filter (lambda (input)
                             (match input
                               ;; Work around the fact that modify-inputs can not
                               ;; delete specific outputs; i.e. here we should keep
                               ;; `(,glib "bin"), but not `(,glib "static").
                               ((label package output)
                                (not (string=? "static" output)))
                               (_ input)))
                           (modify-inputs (package-native-inputs qemu)
                             (delete "gettext-minimal"))))
    (inputs (modify-inputs (package-inputs qemu)
              (delete "libusb"
                      "mesa"
                      "sdl2"
                      "spice"
                      "virglrenderer"
                      "gtk+"
                      "usbredir"
                      "libdrm"
                      "libepoxy"
                      "pulseaudio"
                      "vde2"
                      "libcacard")))))

;;; and then I c/p here to build with guix package
myqemu