package/python-ujson: needs C++

python-ujson needs C++ since bump to version 4.1.0 in commit
a47f332a20bf3f79ef4903c8ddd2b7917217e354 and
https://github.com/ultrajson/ultrajson/commit/eb7d894f225bb89d269188ba6ec559b914a71b8a:

powerpc-buildroot-linux-gnu-gcc.br_real: error: ./deps/double-conversion/double-conversion/bignum-dtoa.cc: C++ compiler not installed on this system

Fixes:
 - http://autobuild.buildroot.org/results/b11600bdba42be9b211163e92afa3173276c3f8f

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/python-ujson/Config.in

@@ -1,7 +1,11 @@
 config BR2_PACKAGE_PYTHON_UJSON
 	bool "python-ujson"
+	depends on BR2_INSTALL_LIBSTDCPP
 	help
 	  UltraJSON is an ultra fast JSON encoder and decoder written
 	  in pure C with bindings for Python 3.
 
 	  https://pypi.python.org/pypi/ujson
+
+comment "python-ujson needs a toolchain w/ C++"
+	depends on !BR2_INSTALL_LIBSTDCPP