build-sys: fix {release-version} man pages

* define {release-version} as $VERSION

* do not use {docdir} in adoc; it's built-in ascidoctor variable
  https://docs.asciidoctor.org/asciidoc/latest/attributes/document-attributes-reference/#intrinsic-attributes

Addresses: https://github.com/karelzak/util-linux/issues/1327
Signed-off-by: Karel Zak <kzak@redhat.com>

Makefile.am

@@ -205,6 +205,8 @@ $(MANPAGES): $(ADOCFILES_COMMON) Makefile
 
 asciidoc_man_cmd = $(ASCIIDOCTOR) \
 	-b manpage \
+	-a 'release-version=$(VERSION)' \
+	-a 'package-docdir=$(docdir)' \
 	-a 'VERSION=$(VERSION)' \
 	-a 'ADJTIME_PATH=$(ADJTIME_PATH)'
 

misc-utils/getopt.1.adoc

@@ -129,8 +129,8 @@ In compatibility mode, leading '*-*' and '*{plus}*' characters in the short opti
 
 == EXAMPLES
 
-// TRANSLATORS: Don't translate _{docdir}_.
-Example scripts for (ba)sh and (t)csh are provided with the *getopt*(1) distribution, and are installed in _{docdir}_ directory.
+// TRANSLATORS: Don't translate _{package-docdir}_.
+Example scripts for (ba)sh and (t)csh are provided with the *getopt*(1) distribution, and are installed in _{package-docdir}_ directory.
 
 == ENVIRONMENT