configure: simplify creation of plugin symbol list

--dynamic-list is present on all supported ELF (not Windows or Darwin)
platforms, since it dates back to 2006; -exported_symbols_list is
likewise present on all supported versions of macOS.  Do not bother
doing a functional test in configure.

Remove the file creation from configure as well: for Darwin, move the
the creation of the Darwin-formatted symbols to meson; for ELF, use the
file in the source path directly and switch from -Wl, to -Xlinker to
not break weird paths that include a comma.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -78,7 +78,6 @@ TMPC="${TMPDIR1}/${TMPB}.c"
 TMPO="${TMPDIR1}/${TMPB}.o"
 TMPCXX="${TMPDIR1}/${TMPB}.cxx"
 TMPE="${TMPDIR1}/${TMPB}.exe"
-TMPTXT="${TMPDIR1}/${TMPB}.txt"
 
 rm -f config.log
 
@@ -1696,6 +1695,7 @@ if test "$static" = "yes" ; then
     plugins="no"
   fi
 fi
+test "$plugins" = "" && plugins=yes
 
 cat > $TMPC << EOF
 
@@ -2317,69 +2317,6 @@ EOF
     fi
 fi
 
-##########################################
-# plugin linker support probe
-
-if test "$plugins" != "no"; then
-
-    #########################################
-    # See if --dynamic-list is supported by the linker
-
-    ld_dynamic_list="no"
-    cat > $TMPTXT <<EOF
-{
-  foo;
-};
-EOF
-
-        cat > $TMPC <<EOF
-#include <stdio.h>
-void foo(void);
-
-void foo(void)
-{
-  printf("foo\n");
-}
-
-int main(void)
-{
-  foo();
-  return 0;
-}
-EOF
-
-    if compile_prog "" "-Wl,--dynamic-list=$TMPTXT" ; then
-        ld_dynamic_list="yes"
-    fi
-
-    #########################################
-    # See if -exported_symbols_list is supported by the linker
-
-    ld_exported_symbols_list="no"
-    cat > $TMPTXT <<EOF
-  _foo
-EOF
-
-    if compile_prog "" "-Wl,-exported_symbols_list,$TMPTXT" ; then
-        ld_exported_symbols_list="yes"
-    fi
-
-    if test "$ld_dynamic_list" = "no" &&
-       test "$ld_exported_symbols_list" = "no" ; then
-        if test "$plugins" = "yes"; then
-            error_exit \
-                "Plugin support requires dynamic linking and specifying a set of symbols " \
-                "that are exported to plugins. Unfortunately your linker doesn't " \
-                "support the flag (--dynamic-list or -exported_symbols_list) used " \
-                "for this purpose."
-        else
-            plugins="no"
-        fi
-    else
-        plugins="yes"
-    fi
-fi
-
 ##########################################
 # glib support probe
 
@@ -3614,22 +3551,6 @@ fi
 
 if test "$plugins" = "yes" ; then
     echo "CONFIG_PLUGIN=y" >> $config_host_mak
-    # Copy the export object list to the build dir
-    if test "$ld_dynamic_list" = "yes" ; then
-	echo "CONFIG_HAS_LD_DYNAMIC_LIST=yes" >> $config_host_mak
-	ld_symbols=qemu-plugins-ld.symbols
-	cp "$source_path/plugins/qemu-plugins.symbols" $ld_symbols
-    elif test "$ld_exported_symbols_list" = "yes" ; then
-	echo "CONFIG_HAS_LD_EXPORTED_SYMBOLS_LIST=yes" >> $config_host_mak
-	ld64_symbols=qemu-plugins-ld64.symbols
-	echo "# Automatically generated by configure - do not modify" > $ld64_symbols
-	grep 'qemu_' "$source_path/plugins/qemu-plugins.symbols" | sed 's/;//g' | \
-	    sed -E 's/^[[:space:]]*(.*)/_\1/' >> $ld64_symbols
-    else
-	error_exit \
-	    "If \$plugins=yes, either \$ld_dynamic_list or " \
-	    "\$ld_exported_symbols_list should have been set to 'yes'."
-    fi
 fi
 
 if test -n "$gdb_bin"; then

plugins/meson.build

@@ -1,10 +1,15 @@
 plugin_ldflags = []
 # Modules need more symbols than just those in plugins/qemu-plugins.symbols
 if not enable_modules
-  if 'CONFIG_HAS_LD_DYNAMIC_LIST' in config_host
-    plugin_ldflags = ['-Wl,--dynamic-list=qemu-plugins-ld.symbols']
-  elif 'CONFIG_HAS_LD_EXPORTED_SYMBOLS_LIST' in config_host
-    plugin_ldflags = ['-Wl,-exported_symbols_list,qemu-plugins-ld64.symbols']
+  if targetos == 'darwin'
+    qemu_plugins_symbols_list = configure_file(
+      input: files('qemu-plugins.symbols'),
+      output: 'qemu-plugins-ld64.symbols',
+      capture: true,
+      command: ['sed', '-ne', 's/^[[:space:]]*\\(qemu_.*\\);/_\\1/p', '@INPUT@'])
+    plugin_ldflags = ['-Wl,-exported_symbols_list,plugins/qemu-plugins-ld64.symbols']
+  else
+    plugin_ldflags = ['-Xlinker', '--dynamic-list=' + (meson.project_source_root() / 'plugins/qemu-plugins.symbols')]
   endif
 endif