Issue #15819: use standard autoconf preset output variables.
Reported by: Roumen Petrov
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 4ff801b..9c83248 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -27,7 +27,8 @@
VERSION= @VERSION@
srcdir= @srcdir@
VPATH= @srcdir@
-BUILDDIR= @BUILDDIR@
+abs_srcdir= @abs_srcdir@
+abs_builddir= @abs_builddir@
CC= @CC@
diff --git a/configure b/configure
index a619bb3..6e1825f 100755
--- a/configure
+++ b/configure
@@ -715,7 +715,6 @@
HGTAG
HGVERSION
BASECPPFLAGS
-BUILDDIR
target_alias
host_alias
build_alias
@@ -2721,10 +2720,8 @@
-BUILDDIR="`pwd`"
-
-if test "$srcdir" != "." -a "$srcdir" != "$BUILDDIR"; then
+if test "$abs_srcdir" != "$abs_builddir"; then
# If we're building out-of-tree, we need to make sure the following
# resources get picked up before their $srcdir counterparts.
# Objects/ -> typeslots.inc
diff --git a/configure.ac b/configure.ac
index 04413e9..4eb6c43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,10 +9,8 @@
AC_INIT(python, PYTHON_VERSION, http://bugs.python.org/)
-BUILDDIR="`pwd`"
-AC_SUBST(BUILDDIR)
AC_SUBST(BASECPPFLAGS)
-if test "$srcdir" != "." -a "$srcdir" != "$BUILDDIR"; then
+if test "$abs_srcdir" != "$abs_builddir"; then
# If we're building out-of-tree, we need to make sure the following
# resources get picked up before their $srcdir counterparts.
# Objects/ -> typeslots.inc