[LyX/2.3.x] Add missing hunspell header to the sources

[Juergen Spitzmueller]

commit d882b20e2259f004763ee8838c5864cb2e3213b0
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Thu Dec 15 08:23:45 2022 +0100

    Add missing hunspell header to the sources
    
    This should fix Yu Gin's building woes on Windows.
---
 3rdparty/hunspell/Makefile.am |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/3rdparty/hunspell/Makefile.am b/3rdparty/hunspell/Makefile.am
index cb9341f..2644988 100644
--- a/3rdparty/hunspell/Makefile.am
+++ b/3rdparty/hunspell/Makefile.am
@@ -59,4 +59,5 @@ liblyxhunspell_a_SOURCES = \
 	1.7.0/src/parsers/textparser.cxx \
 	1.7.0/src/parsers/textparser.hxx \
 	1.7.0/src/parsers/xmlparser.cxx \
-	1.7.0/src/parsers/xmlparser.hxx
+	1.7.0/src/parsers/xmlparser.hxx \
+	1.7.0/src/win_api/config.h