[Buildroot] [git commit branch/2021.02.x] package/python-pysftp: add missing C++ dependency from paramiko

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=0898fde96832ade8b7143f64dd4a1ad7e37cb20f
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2021.02.x

python-paramiko has a dependency on C++ support, which was added in
commit 2d7b73cf75daedd4a198a75546308fedae7c9467 in 2016.

When python-pysftp was added in commit
3b920487bad119abf5bfb10a237cedd3b5278c10 in 2020, this C++ dependency
was not propagated, even though python-pysftp selects python-paramiko.

This commit fixes this issue by propagating the dependency, which
fixes this warning:

WARNING: unmet direct dependencies detected for BR2_PACKAGE_PYTHON_PARAMIKO
  Depends on [n]: (BR2_PACKAGE_PYTHON [=n] || BR2_PACKAGE_PYTHON3 [=y]) && BR2_PACKAGE_PYTHON3 [=y] && BR2_INSTALL_LIBSTDCPP [=n]
  Selected by [y]:
  - BR2_PACKAGE_PYTHON_PYSFTP [=y] && (BR2_PACKAGE_PYTHON [=n] || BR2_PACKAGE_PYTHON3 [=y]) && BR2_PACKAGE_PYTHON3 [=y]

That occurs with configuration with C++ disabled, but python-pysftp
enabled.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit 8d1a72866a9eab1502a9cf4ebcf86e35cf8fc7db)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/python-pysftp/Config.in | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/package/python-pysftp/Config.in b/package/python-pysftp/Config.in
index 06f883f602..0866df3055 100644
--- a/package/python-pysftp/Config.in
+++ b/package/python-pysftp/Config.in
@@ -1,7 +1,11 @@
 config BR2_PACKAGE_PYTHON_PYSFTP
 	bool "python-pysftp"
+	depends on BR2_INSTALL_LIBSTDCPP # python-paramiko
 	select BR2_PACKAGE_PYTHON_PARAMIKO # runtime
 	help
 	  A friendly face on SFTP.
 
 	  https://bitbucket.org/dundeemt/pysftp
+
+comment "python-pysftp needs a toolchain w/ C++"
+	depends on !BR2_INSTALL_LIBSTDCPP