[PATCH] contrib: Improve dg-extract-results.sh's Python detection

[Sam James <sam@gentoo.org>]

'python' on some systems (e.g. SLES 15) might be Python 2. Prefer ${EPYTHON}
if defined (used by Gentoo's python-exec wrapping), then python3, then python.

contrib/ChangeLog:

    * dg-extract-results.sh: Check for python3 before python.
---
 contrib/dg-extract-results.sh | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/contrib/dg-extract-results.sh b/contrib/dg-extract-results.sh
index 00ef80046f74..2d1cd76fe255 100755
--- a/contrib/dg-extract-results.sh
+++ b/contrib/dg-extract-results.sh
@@ -28,14 +28,17 @@
 
 PROGNAME=dg-extract-results.sh
 
-# Try to use the python version if possible, since it tends to be faster.
+# Try to use the python version if possible, since it tends to be faster and
+# produces more stable results.
 PYTHON_VER=`echo "$0" | sed 's/sh$/py/'`
-if test "$PYTHON_VER" != "$0" &&
-   test -f "$PYTHON_VER" &&
-   python -c 'import sys, getopt, re, io, datetime, operator; sys.exit (0 if sys.version_info >= (2, 6) else 1)' \
-     > /dev/null 2> /dev/null; then
-  exec python $PYTHON_VER "$@"
-fi
+for python in ${EPYTHON:-python3} python ; do
+	if test "$PYTHON_VER" != "$0" &&
+	   test -f "$PYTHON_VER" &&
+	   ${python} -c 'import sys, getopt, re, io, datetime, operator; sys.exit (0 if sys.version_info >= (2, 6) else 1)' \
+	     > /dev/null 2> /dev/null; then
+	  exec ${python} $PYTHON_VER "$@"
+	fi
+done
 
 usage() {
   cat <<EOF >&2
-- 
2.44.0