lirc-tools: needs a C++ toolchain

lirc-tools: needs a C++ toolchain

NEWS file record for version 0.9.3:

  * The compiler has been switched to c++, and filenames are
	updated to *.cpp (#79)

Fixes:
http://autobuild.buildroot.net/results/63b/63b1e427df1d6f264517a028655ac80d8d289254/
http://autobuild.buildroot.net/results/340/3409a4af78c83ea354d861052521f634347cd69a/
http://autobuild.buildroot.net/results/88a/88a117c229286ed739bd0ef832fa01a99825286a/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>