distutils/setuptools-native, distutils3/setuptools3-native: do not try to fetch code during do_compile

If a python recipe is using setuptools and the setup_requires argument, where
setuptools will use easy_install to fetch the module if it isn't
present.

The build failed on a machine where a proxy was required, but succeeded on a
machine which had direct access to the internet

Add var-NO_FETCH_BUILD, and set it in distutils_do_compile which does not
allow to fetch code from internet during do_compile.

Example result:
...
ERROR: Do not try to fetch `pytest-runner1' for building. Please add its native recipe to DEPENDS.
Traceback (most recent call last):
  File "setup.py", line 56, in <module>
...

The improvement is flexible for test_requirements argument (used at
`setup.py test'), where use easy_install also.

[YOCTO #12084]
(From OE-Core rev: 57414f4a1c549e6faaa110e6e95ff601b05b7361)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/distutils.bbclass

@@ -8,6 +8,7 @@ DISTUTILS_INSTALL_ARGS ?= "--prefix=${D}/${prefix} \
     --install-data=${D}/${datadir}"
 
 distutils_do_compile() {
+         NO_FETCH_BUILD=1 \
          STAGING_INCDIR=${STAGING_INCDIR} \
          STAGING_LIBDIR=${STAGING_LIBDIR} \
          ${STAGING_BINDIR_NATIVE}/${PYTHON_PN}-native/${PYTHON_PN} setup.py build ${DISTUTILS_BUILD_ARGS} || \