[LyX/master] Copy-paste error in spell.m4.

[Pavel Sanda]

commit 2686efbf7b774dca8d7af94e1985ff54342bf749
Author: Pavel Sanda <sanda at lyx.org>
Date:   Mon Aug 14 22:26:20 2023 +0200

    Copy-paste error in spell.m4.
    
    Reported by Nusret Balci.
---
 config/spell.m4 |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/config/spell.m4 b/config/spell.m4
index f291670..988f5ea 100644
--- a/config/spell.m4
+++ b/config/spell.m4
@@ -61,7 +61,7 @@ AC_DEFUN([LYX_HAVE_HUNSPELL_CXXABI],
 [
   AC_MSG_CHECKING([whether hunspell C++ (rather than C) ABI is provided])
   save_CXXFLAGS=$CXXFLAGS
-  CXXFLAGS="$ENCHANT_CFLAGS $AM_CXXFLAGS $CXXFLAGS"
+  CXXFLAGS="$HUNSPELL_CFLAGS $AM_CXXFLAGS $CXXFLAGS"
 
 # in the C++ ABI, stem() returns a vector, in the C ABI, it returns an int
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <hunspell/hunspell.hxx>]], [[Hunspell sp("foo", "bar");