upmendex: unbundle from texlive_core

The category is again an estimation, there is no separate package in Gentoo.

app-text/texlive_core/texlive_core-2024.2.recipe

@@ -413,7 +413,6 @@ PROVIDES="
 	cmd:updvitype
 	cmd:uplatex
 	cmd:uplatex_dev
-	cmd:upmendex
 	cmd:upmpost
 	cmd:uppltotf
 	cmd:uptex
@@ -628,7 +627,6 @@ defineDebugInfoPackage texlive_core$secondaryArchSuffix \
 	$prefix/bin/twill \
 	$prefix/bin/upbibtex \
 	$prefix/bin/updvitype \
-	$prefix/bin/upmendex \
 	$prefix/bin/upmpost \
 	$prefix/bin/uppltotf \
 	$prefix/bin/uptex \
@@ -823,6 +821,7 @@ BUILD()
 		--disable-lcdf-typetools \
 		--disable-musixtnt \
 		--disable-psutils \
+		--disable-upmendex \
 		--disable-t1utils \
 		--build=$HOST --host=$HOST