build,cpp: Support building C++ bindings as nested package of gpgme

* Makefile.am: Add variables languages, dist_languages,
distcheck_languages, release_languages, sign_release_languages,
distclean_languages. Add rules for nested language bindings.
(distclean-local, dist-all, distcheck-all, release-all,
sign-release-all): New rules.
(.PHONY): Add all new rules.
* autogen-all.sh: New.
* configure.ac: Add cpp to available languages if subdir exists. Add
cpp to nested languages if enabled to generate corresponding make
targets. Call configure script of nested cpp package recursively.
* lang/cpp/configure.ac: Check if gpgmepp is built as nested package
and set GPGME_CFLAGS and GPGME_LIBS accordingly.
--

This re-adds the ability to build the C++ bindings together with gpgme
with a single `configure && make` command (if building from git). It
also adds make targets for running dist, distcheck, release and
sign-release for gpgme and all enabled nested languages with a single
make command.

GnuPG-bug-id: 7110

Makefile.am

@@ -1,6 +1,6 @@
 # Makefile.am - Top level Makefile for GPGME.
 # Copyright (C) 2000 Werner Koch (dd9jn)
-# Copyright (C) 2001, 2002, 2004, 2005, 2008, 2009 g10 Code GmbH
+# Copyright (C) 2001, 2002, 2004, 2005, 2008, 2009, 2024 g10 Code GmbH
 #
 # This file is part of GPGME.
 #
@@ -70,8 +70,6 @@ distcheck-hook:
 	  esac;\
 	done ) | tee $(distdir).swdb
 
-.PHONY: gen-ChangeLog release sign-release
-
 gen_start_date = 2011-12-01T00:00:00
 gen-ChangeLog:
 	if test -d $(top_srcdir)/.git; then				\
@@ -142,3 +140,58 @@ sign-release:
 	  echo ' * All done; for checksums see dist/swdb.snippet' ;\
 	  echo ' */' ;\
          )
+
+languages = $(NESTED_LANGUAGES)
+
+dist_languages = $(languages:%=dist-%)
+$(dist_languages):
+	+(set -e;\
+	  lang=$$(echo "$@" | sed 's/.*-//');\
+	  cd "lang/$$lang";\
+	  $(MAKE) dist;\
+	)
+
+distcheck_languages = $(languages:%=distcheck-%)
+$(distcheck_languages):
+	+(set -e;\
+	  lang=$$(echo "$@" | sed 's/.*-//');\
+	  cd "lang/$$lang";\
+	  $(MAKE) distcheck;\
+	)
+
+release_languages = $(languages:%=release-%)
+$(release_languages):
+	+(set -e;\
+	  lang=$$(echo "$@" | sed 's/.*-//');\
+	  cd "lang/$$lang";\
+	  $(MAKE) release;\
+	)
+
+sign_release_languages = $(languages:%=sign-release-%)
+$(sign_release_languages):
+	+(set -e;\
+	  lang=$$(echo "$@" | sed 's/.*-//');\
+	  cd "lang/$$lang";\
+	  $(MAKE) sign-release;\
+	)
+
+distclean_languages = $(languages:%=distclean-%)
+$(distclean_languages):
+	+(set -e;\
+	  lang=$$(echo "$@" | sed 's/.*-//');\
+	  cd "lang/$$lang";\
+	  $(MAKE) distclean;\
+	)
+distclean-local: $(distclean_languages)
+
+dist-all: dist $(dist_languages)
+
+distcheck-all: distcheck $(distcheck_languages)
+
+release-all: release $(release_languages)
+
+sign-release-all: sign-release $(sign_release_languages)
+
+.PHONY: gen-ChangeLog release sign-release dist-all $(dist_languages) \
+	distcheck-all $(distcheck_languages) release-all $release_languages) \
+	sign-release-all $(sign_release_languages) $(distclean_languages)

autogen-all.sh

@@ -0,0 +1,67 @@
+#! /bin/sh
+# autogen-all.sh
+# Copyright (C) 2024 g10 Code GmbH
+#
+# This file is free software; as a special exception the author gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# This script is a helper to run the autogen.sh script for gpgme and the
+# nested packages of the C++, Qt, and Python bindings.
+
+prog=$(basename "$0")
+
+packages=". lang/cpp"
+
+fatal () {
+    echo "${prog}:" "$*" >&2
+    DIE=yes
+}
+
+info () {
+    if [ -z "${SILENT}" ]; then
+      echo "${prog}:" "$*" >&2
+    fi
+}
+
+die_p () {
+  if [ "$DIE" = "yes" ]; then
+    echo "autogen.sh: Stop." >&2
+    exit 1
+  fi
+}
+
+DIE=no
+SILENT=
+tmp=$(dirname "$0")
+tsdir=$(cd "${tmp}"; pwd)
+
+am_lf='
+'
+
+if test x"$1" = x"--help"; then
+  tmp="$(pwd)"
+  cd "$tsdir" || fatal "error cd-ing to $tsdir"
+  die_p
+  ./autogen.sh --help | sed "s/autogen.sh/${prog}/" || fatal "error running ./autogen.sh --help"
+  die_p
+  exit 0
+fi
+if test x"$1" = x"--silent"; then
+  SILENT=" --silent"
+fi
+
+for p in $packages; do
+  info Running ./autogen.sh "$@" in $p ...
+  curdir="$(pwd)"
+  cd "$tsdir/$p" || fatal "error cd-ing to $tsdir/$p"
+  die_p
+  ./autogen.sh "$@" | sed "s/autogen.sh/${prog}/" || fatal "error running ./autogen.sh $@"
+  die_p
+  cd "$curdir" || fatal "error cd-ing back to $curdir"
+  die_p
+done

configure.ac

@@ -238,6 +238,11 @@ have_macos_system=no
 build_w32_glib=no
 available_languages="cl"
 default_languages="cl"
+for lang in cpp; do
+  if test -d $srcdir/lang/$lang; then
+    available_languages="$available_languages $lang"
+  fi
+done
 case "${host}" in
     x86_64-*mingw32*)
         have_w64_system=yes
@@ -323,8 +328,7 @@ fi
 #       lang/Makefile.am's DIST_SUBDIRS.
 AC_ARG_ENABLE([languages],
               AS_HELP_STRING([--enable-languages=languages],
-                             [enable only specific language bindings:
+                             [enable only specific language bindings]),
-                              cl]),
                              [enabled_languages=`echo $enableval | \
                              tr ',:' '  ' | tr '[A-Z]' '[a-z]'`],
                              [enabled_languages="maybe"])
@@ -351,6 +355,14 @@ done
 
 AC_SUBST(ENABLED_LANGUAGES, $enabled_languages)
 
+nested_languages=
+LIST_MEMBER("cpp", $enabled_languages)
+if test "$found" = "1"; then
+  nested_languages="$nested_languages cpp"
+fi
+
+AC_SUBST(NESTED_LANGUAGES, $nested_languages)
+
 #
 # Provide information about the build.
 #
@@ -825,6 +837,13 @@ AC_CONFIG_FILES([lang/Makefile lang/cl/Makefile lang/cl/gpgme.asd])
 AC_CONFIG_FILES([lang/js/Makefile lang/js/src/Makefile
                  lang/js/BrowserTestExtension/Makefile
                  lang/js/DemoExtension/Makefile])
+
+# Call ./configure scripts of nested packages recursively.
+LIST_MEMBER("cpp", $enabled_languages)
+if test "$found" = "1"; then
+  AC_CONFIG_SUBDIRS([lang/cpp])
+fi
+
 AC_OUTPUT
 
 echo "

lang/cpp/configure.ac

@@ -354,8 +354,26 @@ AM_CONDITIONAL(USE_GPGRT_CONFIG, [test -n "$GPGRT_CONFIG" \
 
 # And for gpgme.
 have_gpgme=no
-AM_PATH_GPGME("$NEED_GPGME_VERSION",
+builddir=`pwd`
-              have_gpgme=yes, have_gpgme=no)
+# Check if gpgmepp is built as nested package of gpgme
+if test "${srcdir%/lang/cpp}/lang/cpp" == "$srcdir" -a \
+        "${builddir%/lang/cpp}/lang/cpp" == "$builddir"; then
+  AC_MSG_CHECKING(for GpgME - assuming nested build)
+  gpgme_build_dir=${builddir%/lang/cpp}
+  if test -f "$gpgme_build_dir/src/gpgme.h"; then
+    GPGME_CFLAGS="-I$gpgme_build_dir/src"
+    GPGME_LIBS="$gpgme_build_dir/src/libgpgme.la"
+    have_gpgme=yes
+    AC_MSG_RESULT(yes)
+  else
+    AC_MSG_RESULT(no)
+  fi
+fi
+
+if test "$have_gpgme" = "no"; then
+  AM_PATH_GPGME("$NEED_GPGME_VERSION",
+                have_gpgme=yes, have_gpgme=no)
+fi
 
 
 # Substitution used for gpgmepp.pc