command: add libplacebo-version property

Similar to other core library dependencies.

DOCS/interface-changes/libplacebo-version.txt

@@ -0,0 +1 @@
+add `libplacebo-version` property

DOCS/man/input.rst

@@ -3960,6 +3960,11 @@ Property list
     somewhat weird form (apparently "hex BCD"), indicating the release version
     of the libass library linked to mpv.
 
+``libplacebo-version``
+    The contents of the ``PL_VERSION`` macro. This is a string which identifies
+    the build in some way, either through a release version number, or a git
+    hash.
+
 ``subrandr-version``
     The value of ``sbr_library_version()`` as a string in the format
     ``<major>.<minor>.<patch>``, indicating the release version of the subrandr

player/command.c

@@ -3762,6 +3762,12 @@ static int mp_property_libass_version(void *ctx, struct m_property *prop,
     return m_property_int64_ro(action, arg, ass_library_version());
 }
 
+static int mp_property_libplacebo_version(void *ctx, struct m_property *prop,
+                                          int action, void *arg)
+{
+    return m_property_strdup_ro(action, arg, PL_VERSION);
+}
+
 static int mp_property_subrandr_version(void *ctx, struct m_property *prop,
                                       int action, void *arg)
 {
@@ -4558,6 +4564,7 @@ static const struct m_property mp_properties_base[] = {
     {"mpv-configuration", mp_property_configuration},
     {"ffmpeg-version", mp_property_ffmpeg},
     {"libass-version", mp_property_libass_version},
+    {"libplacebo-version", mp_property_libplacebo_version},
     {"subrandr-version", mp_property_subrandr_version},
     {"platform", mp_property_platform},