python: shut up "pip install" during "make check-minreqs"

"make check-minreqs" runs pip without the --disable-pip-version-check
option, which causes the obnoxious "A new release of pip available"
message.

Recent versions of pip also complain that some of the dependencies in
our virtual environment rely on "setup.py install" instead of providing
a pyproject.toml file; apparently it is deprecated to install them
directly from pip instead of letting the "wheel" package take care
of them.  So, install "wheel" in the virtual environment.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20230511035435.734312-2-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

python/Makefile

@@ -54,6 +54,7 @@ pipenv check-pipenv:
 	@echo "pipenv was dropped; try 'make check-minreqs' or 'make min-venv'"
 	@exit 1
 
+PIP_INSTALL = pip install --disable-pip-version-check
 .PHONY: min-venv
 min-venv: $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate
 $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate: setup.cfg tests/minreqs.txt
@@ -62,10 +63,12 @@ $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate: setup.cfg tests/minreqs.tx
 	@(								\
 		echo "ACTIVATE $(QEMU_MINVENV_DIR)";			\
 		. $(QEMU_MINVENV_DIR)/bin/activate;			\
+		echo "INSTALL wheel $(QEMU_MINVENV_DIR)";               \
+		$(PIP_INSTALL) wheel 1>/dev/null;		               \
 		echo "INSTALL -r tests/minreqs.txt $(QEMU_MINVENV_DIR)";\
-		pip install -r tests/minreqs.txt 1>/dev/null;		\
+		$(PIP_INSTALL) -r tests/minreqs.txt 1>/dev/null;	\
 		echo "INSTALL -e qemu $(QEMU_MINVENV_DIR)";		\
-		pip install -e . 1>/dev/null;				\
+		$(PIP_INSTALL) -e . 1>/dev/null;			\
 	)
 	@touch $(QEMU_MINVENV_DIR)
 
@@ -100,7 +103,7 @@ check-dev: dev-venv
 
 .PHONY: develop
 develop:
-	pip3 install --disable-pip-version-check -e .[devel]
+	$(PIP_INSTALL) -e .[devel]
 
 .PHONY: check
 check: