Deduplicate CLAP extension support queries

They're only queried once now and the booleans are derived from the
stored pointers.

src/common/serialization/clap/host.cpp

@@ -28,8 +28,5 @@ Host::Host(const clap_host_t& original)
       url(original.url ? std::optional(original.url) : std::nullopt),
       version((assert(original.version), original.version)) {}
 
-SupportedHostExtensions::SupportedHostExtensions(const clap_host& host)
-    : supports_audio_ports(host.get_extension(&host, CLAP_EXT_AUDIO_PORTS)) {}
-
 }  // namespace host
 }  // namespace clap

src/common/serialization/clap/host.h

@@ -75,18 +75,11 @@ struct Host {
 
 /**
  * Extensions supported by the host. This can only be queried in
- * `clap_plugin::init()` so it cannot be part of `Host`. We'll create make these
- * same extensions available to the bridged CLAP plugins using proxies.
+ * `clap_plugin::init()` so it cannot be part of `Host`. Created by
+ * `ClapHostExtensions::supported()`. We'll create make these same extensions
+ * available to the bridged CLAP plugins using proxies.
  */
 struct SupportedHostExtensions {
-    /**
-     * Read the supported extensions from a native CLAP host. This is only valid
-     * once the native host has called `clap_host::init()`.
-     */
-    SupportedHostExtensions(const clap_host& host);
-
-    SupportedHostExtensions() noexcept {}
-
     // Don't forget to add new extensions to the log output
     bool supports_audio_ports = false;
 

src/common/serialization/clap/plugin.cpp

@@ -76,9 +76,5 @@ const clap_plugin_descriptor_t* Descriptor::get() const {
     return &clap_descriptor;
 }
 
-SupportedPluginExtensions::SupportedPluginExtensions(const clap_plugin& plugin)
-    : supports_audio_ports(
-          plugin.get_extension(&plugin, CLAP_EXT_AUDIO_PORTS)) {}
-
 }  // namespace plugin
 }  // namespace clap

src/common/serialization/clap/plugin.h

@@ -109,17 +109,10 @@ struct Descriptor {
 };
 
 /**
- * Extensions supported by the plugin. Queried after `clap_plugin::init()`.
+ * Extensions supported by the plugin. Queried after `clap_plugin::init()` and
+ * created by `ClapPluginExtensions::supported()`.
  */
 struct SupportedPluginExtensions {
-    /**
-     * Read the supported extensions from a CLAP plugin. This is only valid
-     * after `clap_plugin::init()` has been called on the plugin.
-     */
-    SupportedPluginExtensions(const clap_plugin& plugin);
-
-    SupportedPluginExtensions() noexcept {}
-
     // Don't forget to add new extensions to the log output
     bool supports_audio_ports = false;