support/testing/tests: switch python-cryptography related tests to glibc

In a follow-up commit, we are about to bump python-cryptography to a
new version, which has the interesting charateristic of using Rust
code. This means python-cryptography will now only be available on
platforms supported by Rust, which for now excludes uclibc-based
configurations (none of the Rust Tier1/Tier2 platforms use uClibc,
there is some uClibc support in Tier3 platforms but they have not been
added to Buildroot for now).

So in preparation for this bump, we switch the few test cases of
Python packages that directly or indirectly use python-cryptography to
use a glibc toolchain. Another impacted test case is the
docker-compose test case, but it already uses a glibc toolchain;

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/test_python_cryptography.py

@@ -3,10 +3,18 @@ from tests.package.test_python import TestPythonPackageBase
 
 class TestPythonPy3Cryptography(TestPythonPackageBase):
     __test__ = True
-    config = TestPythonPackageBase.config + \
+    # Need to use a different toolchain than the default due to
+    # python-cryptography using Rust (not available with uclibc)
+    config = \
         """
+        BR2_arm=y
+        BR2_TOOLCHAIN_EXTERNAL=y
+        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
+        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_ARMV5_EABI_GLIBC_STABLE=y
         BR2_PACKAGE_PYTHON3=y
         BR2_PACKAGE_PYTHON_CRYPTOGRAPHY=y
+        BR2_TARGET_ROOTFS_CPIO=y
+        # BR2_TARGET_ROOTFS_TAR is not set
         """
     sample_scripts = ["tests/package/sample_python_cryptography.py"]
     timeout = 40