configure: Require Python >= 3.5

Python 3.5 is the oldest Python version available on our
supported build platforms, and Python 2 end of life will be 3
weeks after the planned release date of QEMU 4.2.0.  Drop Python
2 support from configure completely, and require Python 3.5 or
newer.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20191016224237.26180-1-ehabkost@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

configure

@@ -903,9 +903,9 @@ fi
 : ${install=${INSTALL-install}}
 # We prefer python 3.x. A bare 'python' is traditionally
 # python 2.x, but some distros have it as python 3.x, so
-# we check that before python2
+# we check that too
 python=
-for binary in "${PYTHON-python3}" python python2
+for binary in "${PYTHON-python3}" python
 do
     if has "$binary"
     then
@@ -1842,8 +1842,8 @@ fi
 
 # Note that if the Python conditional here evaluates True we will exit
 # with status 1 which is a shell 'false' value.
-if ! $python -c 'import sys; sys.exit(sys.version_info < (2,7))'; then
-  error_exit "Cannot use '$python', Python 2 >= 2.7 or Python 3 is required." \
+if ! $python -c 'import sys; sys.exit(sys.version_info < (3,5))'; then
+  error_exit "Cannot use '$python', Python >= 3.5 is required." \
       "Use --python=/path/to/python to specify a supported Python."
 fi
 
@@ -6594,15 +6594,6 @@ if test "$supported_os" = "no"; then
     echo "us upstream at qemu-devel@nongnu.org."
 fi
 
-# Note that if the Python conditional here evaluates True we will exit
-# with status 1 which is a shell 'false' value.
-if ! $python -c 'import sys; sys.exit(sys.version_info < (3,0))'; then
-  echo
-  echo "warning: Python 2 support is deprecated" >&2
-  echo "warning: Python 3 will be required for building future versions of QEMU" >&2
-  python2="y"
-fi
-
 config_host_mak="config-host.mak"
 
 echo "# Automatically generated by configure - do not modify" >config-all-disas.mak
@@ -7447,7 +7438,6 @@ echo "INSTALL_DATA=$install -c -m 0644" >> $config_host_mak
 echo "INSTALL_PROG=$install -c -m 0755" >> $config_host_mak
 echo "INSTALL_LIB=$install -c -m 0644" >> $config_host_mak
 echo "PYTHON=$python" >> $config_host_mak
-echo "PYTHON2=$python2" >> $config_host_mak
 echo "CC=$cc" >> $config_host_mak
 if $iasl -h > /dev/null 2>&1; then
   echo "IASL=$iasl" >> $config_host_mak

tests/Makefile.include

@@ -1157,7 +1157,6 @@ TESTS_RESULTS_DIR=$(BUILD_DIR)/tests/results
 AVOCADO_SHOW=app
 AVOCADO_TAGS=$(patsubst %-softmmu,-t arch:%, $(filter %-softmmu,$(TARGET_DIRS)))
 
-ifneq ($(PYTHON2),y)
 $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
 	$(call quiet-command, \
             $(PYTHON) -m venv --system-site-packages $@, \
@@ -1166,10 +1165,6 @@ $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
             $(TESTS_VENV_DIR)/bin/python -m pip -q install -r $(TESTS_VENV_REQ), \
             PIP, $(TESTS_VENV_REQ))
 	$(call quiet-command, touch $@)
-else
-$(TESTS_VENV_DIR):
-	$(error "venv directory for tests requires Python 3")
-endif
 
 $(TESTS_RESULTS_DIR):
 	$(call quiet-command, mkdir -p $@, \