configure, meson: convert libtasn1 detection to meson

Make it depend on gnutls too, since it is only used as part of gnutls
tests.

Reviewed-by: Richard Henderson <richard.henderson@liaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -2799,20 +2799,6 @@ EOF
   fi
 fi
 
-##########################################
-# libtasn1 - only for the TLS creds/session test suite
-
-tasn1=yes
-tasn1_cflags=""
-tasn1_libs=""
-if $pkg_config --exists "libtasn1"; then
-    tasn1_cflags=$($pkg_config --cflags libtasn1)
-    tasn1_libs=$($pkg_config --libs libtasn1)
-else
-    tasn1=no
-fi
-
-
 ##########################################
 # PAM probe
 
@@ -5554,9 +5540,6 @@ if test "$gdbus_codegen" != "" ; then
     echo "GDBUS_CODEGEN=$gdbus_codegen" >> $config_host_mak
 fi
 echo "CONFIG_TLS_PRIORITY=\"$tls_priority\"" >> $config_host_mak
-if test "$tasn1" = "yes" ; then
-  echo "CONFIG_TASN1=y" >> $config_host_mak
-fi
 if test "$auth_pam" = "yes" ; then
     echo "CONFIG_AUTH_PAM=y" >> $config_host_mak
 fi
@@ -6017,8 +6000,6 @@ echo "LD_I386_EMULATION=$ld_i386_emulation" >> $config_host_mak
 echo "EXESUF=$EXESUF" >> $config_host_mak
 echo "HOST_DSOSUF=$HOST_DSOSUF" >> $config_host_mak
 echo "LIBS_QGA=$libs_qga" >> $config_host_mak
-echo "TASN1_LIBS=$tasn1_libs" >> $config_host_mak
-echo "TASN1_CFLAGS=$tasn1_cflags" >> $config_host_mak
 if test "$gcov" = "yes" ; then
   echo "CONFIG_GCOV=y" >> $config_host_mak
 fi

meson.build

@@ -985,9 +985,10 @@ if 'CONFIG_LIBDAXCTL' in config_host
   libdaxctl = declare_dependency(link_args: config_host['LIBDAXCTL_LIBS'].split())
 endif
 tasn1 = not_found
-if 'CONFIG_TASN1' in config_host
-  tasn1 = declare_dependency(compile_args: config_host['TASN1_CFLAGS'].split(),
-                             link_args: config_host['TASN1_LIBS'].split())
+if gnutls.found()
+  tasn1 = dependency('libtasn1',
+                     method: 'pkg-config',
+                     kwargs: static_kwargs)
 endif
 keyutils = dependency('libkeyutils', required: false,
                       method: 'pkg-config', kwargs: static_kwargs)
@@ -2727,7 +2728,7 @@ summary_info += {'pixman':            pixman.found()}
 summary_info += {'VTE support':       config_host.has_key('CONFIG_VTE')}
 # TODO: add back version
 summary_info += {'slirp support':     slirp_opt == 'disabled' ? false : slirp_opt}
-summary_info += {'libtasn1':          config_host.has_key('CONFIG_TASN1')}
+summary_info += {'libtasn1':          tasn1.found()}
 summary_info += {'PAM':               config_host.has_key('CONFIG_AUTH_PAM')}
 summary_info += {'iconv support':     iconv.found()}
 summary_info += {'curses support':    curses.found()}

tests/unit/meson.build

@@ -84,7 +84,7 @@ if have_block
     'test-crypto-block': [io],
   }
   if gnutls.found() and \
-     'CONFIG_TASN1' in config_host and \
+     tasn1.found() and \
      'CONFIG_POSIX' in config_host
     tests += {
       'test-crypto-tlscredsx509': ['crypto-tls-x509-helpers.c', 'pkix_asn1_tab.c',