Update CMake requeriments

CMakeLists.txt

@@ -36,6 +36,9 @@ ensure_vala_version("0.20" MINIMUM)
 include(ValaPrecompile)
 # make sure we use GettextTranslate
 include(GettextTranslate)
+#
+include(FindPythonModule)
+find_python_module(requests_oauthlib)
 
 
 #indicator

cmake/FindPythonModule.cmake

@@ -0,0 +1,23 @@
+# Copyright 2017 KDE Connect Indicator Developers
+#
+# This software is licensed under the GNU Lesser General Public License
+# (version 2.1 or later).  See the COPYING file in this distribution.
+#
+
+function(find_python_module module)
+	execute_process(
+	COMMAND
+      	python3 -c "from requests_oauthlib import OAuth2Session"
+      	RESULT_VARIABLE PYTHON_module
+	ERROR_QUIET
+      	OUTPUT_STRIP_TRAILING_WHITESPACE
+      	)
+
+	if(NOT PYTHON_module)
+		message ("-- Found requests_oauthlib")
+	else(PYTHON_module)
+		message (FATAL_ERROR "-- Not Found requests_oauthlib: install it first")
+	endif()
+
+endfunction(find_python_module)
+