drop libxml2 checks since libxml is not actually used (for parallels)

For a long time, we assumed that libxml2 is necessary for parallels
block format support (block/parallels*). However, this format actually
does not use libxml [*]. Since this is the only user of libxml2 in
whole QEMU tree, we can drop all libxml2 checks and dependencies too.

It is even more: --enable-parallels configure option was the only
option which was silently ignored when it's (fake) dependency
(libxml2) isn't installed.

Drop all mentions of libxml2.

[*] Actually the basis for libxml use were introduced in commit
    ed279a06c53 ("configure: add dependency") but the implementation
    was never merged:
    https://lore.kernel.org/qemu-devel/70227bbd-a517-70e9-714f-e6e0ec431be9@openvz.org/

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220119090423.149315-1-mjt@msgid.tls.msk.ru>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
[PMD: Updated description and adapted to use lcitool]
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220121154134.315047-5-f4bug@amsat.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20220204204335.1689602-9-alex.bennee@linaro.org>

block/meson.build

@@ -58,8 +58,7 @@ block_ss.add(when: 'CONFIG_QED', if_true: files(
   'qed-table.c',
   'qed.c',
 ))
-block_ss.add(when: [libxml2, 'CONFIG_PARALLELS'],
-             if_true: files('parallels.c', 'parallels-ext.c'))
+block_ss.add(when: 'CONFIG_PARALLELS', if_true: files('parallels.c', 'parallels-ext.c'))
 block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c', 'win32-aio.c'))
 block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit])
 block_ss.add(when: libiscsi, if_true: files('iscsi-opts.c'))

meson.build

@@ -453,11 +453,6 @@ if not get_option('linux_io_uring').auto() or have_block
                               required: get_option('linux_io_uring'),
                               method: 'pkg-config', kwargs: static_kwargs)
 endif
-libxml2 = not_found
-if not get_option('libxml2').auto() or have_block
-  libxml2 = dependency('libxml-2.0', required: get_option('libxml2'),
-                       method: 'pkg-config', kwargs: static_kwargs)
-endif
 libnfs = not_found
 if not get_option('libnfs').auto() or have_block
   libnfs = dependency('libnfs', version: '>=1.9.3',
@@ -3496,7 +3491,6 @@ summary_info += {'bzip2 support':     libbzip2}
 summary_info += {'lzfse support':     liblzfse}
 summary_info += {'zstd support':      zstd}
 summary_info += {'NUMA host support': config_host.has_key('CONFIG_NUMA')}
-summary_info += {'libxml2':           libxml2}
 summary_info += {'capstone':          capstone_opt == 'internal' ? capstone_opt : capstone}
 summary_info += {'libpmem support':   libpmem}
 summary_info += {'libdaxctl support': libdaxctl}

meson_options.txt

@@ -113,8 +113,6 @@ option('libudev', type : 'feature', value : 'auto',
        description: 'Use libudev to enumerate host devices')
 option('libusb', type : 'feature', value : 'auto',
        description: 'libusb support for USB passthrough')
-option('libxml2', type : 'feature', value : 'auto',
-       description: 'libxml2 support for Parallels image format')
 option('linux_aio', type : 'feature', value : 'auto',
        description: 'Linux AIO support')
 option('linux_io_uring', type : 'feature', value : 'auto',

scripts/checkpatch.pl

@@ -307,7 +307,6 @@ our @typeList = (
 	qr{target_(?:u)?long},
 	qr{hwaddr},
         # external libraries
-	qr{xml${Ident}},
 	qr{xen\w+_handle},
 	# Glib definitions
 	qr{gchar},

scripts/ci/org.centos/stream/8/x86_64/configure

@@ -81,7 +81,6 @@
 --disable-libssh \
 --disable-libudev \
 --disable-libusb \
---disable-libxml2 \
 --disable-linux-aio \
 --disable-linux-io-uring \
 --disable-linux-user \

scripts/coverity-scan/coverity-scan.docker

@@ -59,7 +59,6 @@ ENV PACKAGES \
     libubsan \
     libudev-devel \
     libusbx-devel \
-    libxml2-devel \
     libzstd-devel \
     llvm \
     lzo-devel \

scripts/coverity-scan/run-coverity-scan

@@ -402,7 +402,7 @@ echo "Configuring..."
     --enable-libiscsi --enable-libnfs --enable-seccomp \
     --enable-tpm --enable-libssh --enable-lzo --enable-snappy --enable-bzip2 \
     --enable-numa --enable-rdma --enable-smartcard --enable-virglrenderer \
-    --enable-mpath --enable-libxml2 --enable-glusterfs \
+    --enable-mpath --enable-glusterfs \
     --enable-virtfs --enable-zstd
 
 echo "Running cov-build..."

scripts/meson-buildoptions.sh

@@ -58,7 +58,6 @@ meson_options_help() {
   printf "%s\n" '  libssh          ssh block device support'
   printf "%s\n" '  libudev         Use libudev to enumerate host devices'
   printf "%s\n" '  libusb          libusb support for USB passthrough'
-  printf "%s\n" '  libxml2         libxml2 support for Parallels image format'
   printf "%s\n" '  linux-aio       Linux AIO support'
   printf "%s\n" '  linux-io-uring  Linux io_uring support'
   printf "%s\n" '  lzfse           lzfse support for DMG images'
@@ -188,8 +187,6 @@ _meson_option_parse() {
     --disable-libudev) printf "%s" -Dlibudev=disabled ;;
     --enable-libusb) printf "%s" -Dlibusb=enabled ;;
     --disable-libusb) printf "%s" -Dlibusb=disabled ;;
-    --enable-libxml2) printf "%s" -Dlibxml2=enabled ;;
-    --disable-libxml2) printf "%s" -Dlibxml2=disabled ;;
     --enable-linux-aio) printf "%s" -Dlinux_aio=enabled ;;
     --disable-linux-aio) printf "%s" -Dlinux_aio=disabled ;;
     --enable-linux-io-uring) printf "%s" -Dlinux_io_uring=enabled ;;