[gnome-boxes] meson: Add 'uefi' build option

[Felipe Borges <felipeborges src gnome org>]

commit dba00e759c61398f3cbb732387d9793a01347fd9
Author: Fabiano Fidêncio <fidencio redhat com>
Date:   Mon Sep 2 13:11:59 2019 +0200

    meson: Add 'uefi' build option
    
    Let's allow distros to decide whether they'll want to use UEFI firmware
    whenever it's possible or not.
    
    Signed-off-by: Fabiano Fidêncio <fidencio redhat com>

 meson_options.txt        | 5 +++++
 src/meson.build          | 3 +++
 src/vm-configurator.vala | 4 ++++
 3 files changed, 12 insertions(+)
---
diff --git a/meson_options.txt b/meson_options.txt
index c55a4712..a5f1be87 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -29,3 +29,8 @@ option ('profile',
   ],
   value: 'default'
 )
+
+option ('uefi',
+        type: 'boolean',
+        value: true,
+        description: 'Use UEFI whenever it is possible')
diff --git a/src/meson.build b/src/meson.build
index 5b59c3b8..f6d1cffc 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -184,6 +184,9 @@ else
   dependencies += libovf.get_variable('govf_vapi')
 endif
 
+if get_option('uefi')
+    vala_args += '--define=USE_UEFI'
+endif
 
 executable ('gnome-boxes', vala_sources + resources,
             include_directories: config_h_dir,
diff --git a/src/vm-configurator.vala b/src/vm-configurator.vala
index a91aca86..7dba8c49 100644
--- a/src/vm-configurator.vala
+++ b/src/vm-configurator.vala
@@ -368,7 +368,9 @@ private static void set_post_install_os_config (Domain domain) {
 
         os.set_arch (old_os.get_arch ());
         os.set_machine (old_os.get_machine ());
+#if USE_UEFI
         os.set_firmware (old_os.get_firmware ());
+#endif
 
         domain.set_os (os);
     }
@@ -399,8 +401,10 @@ private static void set_os_config (Domain domain, InstallerMedia install_media,
         if (install_media.prefers_q35)
             os.set_machine ("q35");
 
+#if USE_UEFI
         if (supports_efi (install_media, domain_caps))
             os.set_firmware (GVirConfig.DomainOsFirmware.EFI);
+#endif
 
         var boot_devices = new GLib.List<DomainOsBootDevice> ();
         install_media.set_direct_boot_params (os);