[PATCH v3 2/4] docs: replace @xxx@ markers at build time

[Juergen Gross <jgross@xxxxxxxx>]

Use the apply-build-vars make macro to replace the @xxx@ markers in
*.in files only at build time.

This allows to change the affected document files without having to
run "configure" for making the change effective.

While at it add the generated files to the distclean make target.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V2:
- don't rename source files
V3:
- rename IN_FILES to IN_TARGETS (Jan Beulich)
- add only one file to IN_TARGETS per line (Andrew Cooper)
- use $(RM) instead of rm -f (Andrew Cooper)
---
 docs/Makefile     | 11 ++++++++++-
 docs/configure    |  7 +------
 docs/configure.ac |  9 +--------
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/docs/Makefile b/docs/Makefile
index 37776d303c..8e68300e3b 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -8,8 +8,14 @@ DATE           := $(call date,"+%Y-%m-%d")
 DOC_ARCHES      := arm ppc riscv x86_32 x86_64
 MAN_SECTIONS    := 1 5 7 8
 
+IN_TARGETS := man/xl-disk-configuration.5.pod
+IN_TARGETS += man/xl-network-configuration.5.pod
+IN_TARGETS += man/xl.1.pod
+IN_TARGETS += man/xl.cfg.5.pod
+IN_TARGETS += man/xl.conf.5.pod
+
 # Documentation sources to build
-MAN-SRC-y := $(sort $(basename $(wildcard man/*.pod man/*.pandoc)))
+MAN-SRC-y := $(sort $(basename $(wildcard man/*.pod man/*.pandoc) 
$(IN_TARGETS)))
 
 RST-SRC-y := $(sort $(filter-out %index.rst,$(shell find * -type f -name 
'*.rst' -print)))
 
@@ -77,11 +83,14 @@ clean: clean-man-pages
 distclean: clean
        rm -rf $(XEN_ROOT)/config/Docs.mk config.log config.status config.cache 
\
                autom4te.cache
+       $(RM) $(IN_TARGETS)
 
 # Top level install targets
 
 .PHONY: man-pages install-man-pages clean-man-pages uninstall-man-pages
 
+$(foreach file,$(IN_TARGETS),$(eval $(call apply-build-vars,$(file))))
+
 # Metarules for generating manpages.  Run with $(1) substitued for section
 define GENERATE_MANPAGE_RULES
 
diff --git a/docs/configure b/docs/configure
index 98dda3cd0f..8871914dcb 100755
--- a/docs/configure
+++ b/docs/configure
@@ -1794,7 +1794,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-ac_config_files="$ac_config_files ../config/Docs.mk man/xl.cfg.5.pod 
man/xl.1.pod man/xl-disk-configuration.5.pod man/xl-network-configuration.5.pod 
man/xl.conf.5.pod"
+ac_config_files="$ac_config_files ../config/Docs.mk"
 
 
 
@@ -3063,11 +3063,6 @@ for ac_config_target in $ac_config_targets
 do
   case $ac_config_target in
     "../config/Docs.mk") CONFIG_FILES="$CONFIG_FILES ../config/Docs.mk" ;;
-    "man/xl.cfg.5.pod") CONFIG_FILES="$CONFIG_FILES man/xl.cfg.5.pod" ;;
-    "man/xl.1.pod") CONFIG_FILES="$CONFIG_FILES man/xl.1.pod" ;;
-    "man/xl-disk-configuration.5.pod") CONFIG_FILES="$CONFIG_FILES 
man/xl-disk-configuration.5.pod" ;;
-    "man/xl-network-configuration.5.pod") CONFIG_FILES="$CONFIG_FILES 
man/xl-network-configuration.5.pod" ;;
-    "man/xl.conf.5.pod") CONFIG_FILES="$CONFIG_FILES man/xl.conf.5.pod" ;;
 
   *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;
   esac
diff --git a/docs/configure.ac b/docs/configure.ac
index c2e5edd3b3..43dc516056 100644
--- a/docs/configure.ac
+++ b/docs/configure.ac
@@ -5,14 +5,7 @@ AC_PREREQ([2.67])
 AC_INIT([Xen Hypervisor Documentation], m4_esyscmd([../version.sh 
../xen/Makefile]),
     [xen-devel@xxxxxxxxxxxxx], [xen], [https://www.xen.org/])
 AC_CONFIG_SRCDIR([misc/xen-command-line.pandoc])
-AC_CONFIG_FILES([
-../config/Docs.mk
-man/xl.cfg.5.pod
-man/xl.1.pod
-man/xl-disk-configuration.5.pod
-man/xl-network-configuration.5.pod
-man/xl.conf.5.pod
-])
+AC_CONFIG_FILES([../config/Docs.mk])
 AC_CONFIG_AUX_DIR([../])
 
 # M4 Macro includes
-- 
2.51.0