meson: use meson datadir instead of qemu_datadir

When cross-compiling, by default qemu_datadir is 'c:\Program
Files\QEMU', which is not recognized as being an absolute path, and
meson will end up adding the prefix again.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20200826110419.528931-6-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/meson.build b/meson.build
index b68e1bd..6bcfafb 100644
--- a/meson.build
+++ b/meson.build
@@ -18,6 +18,7 @@
 enable_modules = 'CONFIG_MODULES' in config_host
 enable_static = 'CONFIG_STATIC' in config_host
 build_docs = 'BUILD_DOCS' in config_host
+qemu_datadir = get_option('datadir') / get_option('qemu_suffix')
 config_host_data = configuration_data()
 genh = []
 
@@ -1055,7 +1056,7 @@
                       output: exe['name'] + stp['ext'],
                       capture: true,
                       install: stp['install'],
-                      install_dir: config_host['qemu_datadir'] / '../systemtap/tapset',
+                      install_dir: qemu_datadir / '../systemtap/tapset',
                       command: [
                         tracetool, '--group=all', '--format=' + stp['fmt'],
                         '--binary=' + stp['bin'],