bpo-42603: Add whatsnew and ACKS entries. (GH-24675)

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index 26b7076..49681ca 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -1123,6 +1123,12 @@
 
   (Contributed by Victor Stinner in :issue:`43103`.)
 
+* The ``configure`` script now uses the ``pkg-config`` utility, if available,
+  to detect the location of Tcl/Tk headers and libraries.  As before, those
+  locations can be explicitly specified with the ``--with-tcltk-includes``
+  and ``--with-tcltk-libs`` configuration options.
+  (Contributed by Manolis Stamatogiannakis in :issue:`42603`.)
+
 
 C API Changes
 =============
diff --git a/Misc/ACKS b/Misc/ACKS
index ca222e4..d1cee7d 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1660,6 +1660,7 @@
 Tage Stabell-Kulo
 Quentin Stafford-Fraser
 Frank Stajano
+Manolis Stamatogiannakis
 Joel Stanley
 Kyle Stanley
 Brandon Stansbury