build: Add kludge for "make distcheck" in a release build.

* configure.ac: New option --enable-gnupg-builddir-envvar.
(ENABLE_GNUPG_BUILDDIR_ENVVAR): New ac_define.
* common/homedir.c (gnupg_set_builddir_from_env): Consider
ENABLE_GNUPG_BUILDDIR_ENVVAR.
* Makefile.am (DISTCHECK_CONFIGURE_FLAGS): Rename to ...
(AM_DISTCHECK_CONFIGURE_FLAGS): this to be future proof.  Add option
--enable-gnupg-builddir-envvar.

--

Our regression test suite makes use of the envvar GNUPG_BUILDDIR.  Now
the code in gnupg for evaluating this envvar is only included in a
development version (that is one with a "-betaNNN" suffix).  For a
real release the envvar is not considered.  However during a "make
distcheck" a "make check" is done for the build directory.  Without
defining that envar we would try to run binaries in the install
directory ("_inst" sub-directory) which are not yet installed at that
time.

Signed-off-by: Werner Koch <wk@gnupg.org>

Makefile.am

@@ -19,7 +19,8 @@
 ## Process this file with automake to produce Makefile.in
 
 ACLOCAL_AMFLAGS = -I m4
-DISTCHECK_CONFIGURE_FLAGS = --enable-symcryptrun --enable-g13 \
+AM_DISTCHECK_CONFIGURE_FLAGS = --enable-gnupg-builddir-envvar \
+  --enable-symcryptrun --enable-g13 \
   --enable-gpg2-is-gpg --enable-gpgtar --enable-wks-tools --disable-ntbtls
 
 GITLOG_TO_CHANGELOG=gitlog-to-changelog

common/homedir.c

@@ -914,7 +914,7 @@ gnupg_set_builddir (const char *newdir)
 static void
 gnupg_set_builddir_from_env (void)
 {
-#ifdef IS_DEVELOPMENT_VERSION
+#if defined(IS_DEVELOPMENT_VERSION) || defined(ENABLE_GNUPG_BUILDDIR_ENVVAR)
   if (gnupg_build_directory)
     return;
 

configure.ac

@@ -1692,6 +1692,21 @@ AC_ARG_ENABLE(optimization,
                       CFLAGS=`echo $CFLAGS | sed s/-O[[1-9]]\ /-O0\ /g`
                    fi])
 
+#
+# We do not want support for the GNUPG_BUILDDIR environment variable
+# in a released version.  However, our regression tests suite requires
+# this and thus we build with support for it during "make distcheck".
+# This configure option implements this along with the top Makefile's
+# AM_DISTCHECK_CONFIGURE_FLAGS.
+#
+gnupg_builddir_envvar=no
+AC_ARG_ENABLE(gnupg-builddir-envvar,,
+              gnupg_builddir_envvar=$enableval)
+if test x"$gnupg_builddir_envvar" = x"yes"; then
+   AC_DEFINE(ENABLE_GNUPG_BUILDDIR_ENVVAR, 1,
+      [This is only used with "make distcheck"])
+fi
+
 #
 # Add user CFLAGS.
 #