configure: Fix typo

slweb was renamed to libweb some time ago:

commit 28ae865e5ecad9b398ac21fa148fc4b93c987226
Author: Xavier Del Campo Romero <xavi.dcr@tutanota.com>
Date:   Tue Oct 10 23:43:47 2023 +0200

    Apply slweb renaming to libweb

1 files changed, 1 insertions, 1 deletions

diff --git a/configure b/configure
index 886360f..7a674f6 100755
--- a/configure
+++ b/configure
@@ -130,7 +130,7 @@ fi
 if [ $in_tree_libweb -ne 0 ]
 then
 cat <<"EOF" >> $F
-LIBWEB = libweb/libslweb.a
+LIBWEB = libweb/libweb.a
 $(PROJECT): $(LIBWEB)
 $(LIBWEB): FORCE
 	+cd libweb && $(MAKE) CC=$(CC)