meson: Convert fidsk to meson feature

By making this a disabler dependency, we can slightly simplify the code
and it als fixes the build for -Dfdisk=disabled as we failed to create a
fallback empty libshared_fdisk variable.

meson.build

@@ -1119,17 +1119,11 @@ endif
 libmount = dependency('mount',
                       version : fuzzer_build ? '>= 0' : '>= 2.30')
 
-want_libfdisk = get_option('fdisk')
-if want_libfdisk != 'false' and not skip_deps
-        libfdisk = dependency('fdisk',
-                              version : '>= 2.32',
-                              required : want_libfdisk == 'true')
-        have = libfdisk.found()
-else
-        have = false
-        libfdisk = []
-endif
-conf.set10('HAVE_LIBFDISK', have)
+libfdisk = dependency('fdisk',
+                      version : '>= 2.32',
+                      disabler : true,
+                      required : get_option('fdisk'))
+conf.set10('HAVE_LIBFDISK', libfdisk.found())
 
 want_passwdqc = get_option('passwdqc')
 want_pwquality = get_option('pwquality')

meson_options.txt

@@ -373,7 +373,7 @@ option('audit', type : 'feature', deprecated : { 'true' : 'enabled', 'false' : '
        description : 'libaudit support')
 option('blkid', type : 'feature', deprecated : { 'true' : 'enabled', 'false' : 'disabled' },
        description : 'libblkid support')
-option('fdisk', type : 'combo', choices : ['auto', 'true', 'false'],
+option('fdisk', type : 'feature', deprecated : { 'true' : 'enabled', 'false' : 'disabled' },
        description : 'libfdisk support')
 option('kmod', type : 'feature', deprecated : { 'true' : 'enabled', 'false' : 'disabled' },
        description : 'support for loadable modules')

mkosi.presets/base/mkosi.build

@@ -120,7 +120,7 @@ if [ ! -f "$BUILDDIR"/build.ninja ]; then
         -D acl=enabled
         -D audit=enabled
         -D blkid=enabled
-        -D fdisk=true
+        -D fdisk=enabled
         -D kmod=enabled
         -D pam=true
         -D pwquality=true

src/shared/meson.build

@@ -344,13 +344,11 @@ shared_fdisk_sources = files(
         'fdisk-util.c',
 )
 
-if get_option('fdisk') != 'false'
-        libshared_fdisk = static_library(
-                'shared-fdisk',
-                shared_fdisk_sources,
-                include_directories : includes,
-                dependencies : [libfdisk,
-                                userspace],
-                c_args : ['-fvisibility=default'],
-                build_by_default : false)
-endif
+libshared_fdisk = static_library(
+        'shared-fdisk',
+        shared_fdisk_sources,
+        include_directories : includes,
+        dependencies : [libfdisk,
+                        userspace],
+        c_args : ['-fvisibility=default'],
+        build_by_default : false)