buildsys: fix %pkglibexecdir% leaking into man pages in some cases

The generated "doc/man/es/Makefile" contains

	pkglibexecdir = $(libexecdir)/mc
	libexecdir = ${exec_prefix}/libexec
	SED_PARAMETERS = \
		... \
		-e "s{%libexecdir%{${exec_prefix}/libexec{g" \
		-e "s{%pkglibexecdir%{@pkglibexecdir@{g" \

I think "@pkglibexecdir@" is an Automake macro that should have been expanded
when generating this Makefile.

When I install from source, this leads to

	$ man mc | grep bash
	shell to the last directory Midnight Commander was in. Source the file @pkglibexecdir@/mc.sh (bash and zsh

Fix that by using the Make variables.

Regression introduced in 4583127.

Signed-off-by: Johannes Altmanninger <aclopte@gmail.com>
Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

Author: krobelus

doc/man/date-of-man-include.am

@@ -1,10 +1,10 @@
 SED_PARAMETERS = \
 	-e "s/%DATE_OF_MAN_PAGE%/$${MAN_DATE}/g" \
-	-e "s/%MAN_VERSION%/@MAN_VERSION@/g" \
-	-e "s{%sysconfdir%{@sysconfdir@{g" \
-	-e "s{%libexecdir%{@libexecdir@{g" \
-	-e "s{%pkglibexecdir%{@pkglibexecdir@{g" \
-	-e "s{%pkgdatadir%{$(datadir)/@PACKAGE@{g"
+	-e "s/%MAN_VERSION%/$(MAN_VERSION)/g" \
+	-e "s{%sysconfdir%{$(sysconfdir){g" \
+	-e "s{%libexecdir%{$(libexecdir){g" \
+	-e "s{%pkglibexecdir%{$(pkglibexecdir){g" \
+	-e "s{%pkgdatadir%{$(pkgdatadir){g"
 
 MAN_DATE_CMD = \
 	LC_ALL=$(DATE_LANG) @PERL_FOR_BUILD@ -CS -MPOSIX -e '\