gh-145455: Show output of blurb & sphinx-build version commands (GH-145457)

In gh-145455, an outdated dependency caused an import error that was not
printed out (`2>&1`); the message instead said that the tools are missing.

Don't redirect stderr, to show warnings and failures.

Also, switch `blurb` to output a version on a single line (`--version` rather
than `help`), and, and don't redirect stdout either.
This results in two version info lines being printed out. These get drowned
in typical Sphinx output, and can be helpful when debugging.

diff --git a/Doc/Makefile b/Doc/Makefile
index d39c2fe3c3f22adeeb9b80615a406b3507318c84..5b7fdf8ec08ed40cffaffb8bad3e69a677458fee 100644 (file)
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -58,7 +58,7 @@ build:
        @if [ -f  ../Misc/NEWS ] ; then \
                echo "Using existing Misc/NEWS file"; \
                cp ../Misc/NEWS build/NEWS; \
-       elif $(BLURB) help >/dev/null 2>&1 && $(SPHINXBUILD) --version >/dev/null 2>&1; then \
+       elif $(BLURB) --version && $(SPHINXBUILD) --version ; then \
                if [ -d ../Misc/NEWS.d ]; then \
                        echo "Building NEWS from Misc/NEWS.d with blurb"; \
                        $(BLURB) merge -f build/NEWS; \