package/python-sip: disable parallel install

{host-}python-sip may fail to install on fast machine, so disable
parallel install.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/8350440972 (TestPythonPyQt5)
http://autobuild.buildroot.org/results/8f2/8f24656f3a66d21f2d3c6d6b1adc6bb5f1c0c801 (2024-10-15)
http://autobuild.buildroot.org/results/6e6/6e6bbee714b10e0f04c9d17b7e0ecce057d21d2a (2022-07-15)

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 4b271906a74ab773ff276cf5d6d90209c4d32cab)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python-sip/python-sip.mk

@@ -21,8 +21,10 @@ define HOST_PYTHON_SIP_BUILD_CMDS
 	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) -C $(@D)
 endef
 
+# Race condition on fast machine between sipconfig.py install and
+# {sipdistutils.py,mk_distinfo.py} scripts.
 define HOST_PYTHON_SIP_INSTALL_CMDS
-	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE) install -C $(@D)
+	$(HOST_MAKE_ENV) $(HOST_CONFIGURE_OPTS) $(MAKE1) install -C $(@D)
 endef
 
 define PYTHON_SIP_CONFIGURE_CMDS
@@ -42,8 +44,10 @@ define PYTHON_SIP_BUILD_CMDS
 	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)
 endef
 
+# Race condition on fast machine between sipconfig.py install and
+# {sipdistutils.py,mk_distinfo.py} scripts.
 define PYTHON_SIP_INSTALL_TARGET_CMDS
-	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) install -C $(@D)
+	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE1) install -C $(@D)
 endef
 
 $(eval $(generic-package))