lirc-tools: needs threads

Fixes:
http://autobuild.buildroot.net/results/c20/c20a98dfacfa79579a0d401e081f2cca13a7a7b0/
http://autobuild.buildroot.net/results/0fe/0fe9b4a3a5128844886e4bf89b5bc0d3008b43aa/
http://autobuild.buildroot.net/results/482/4826409b3d3177eff3e7f2c3b7360058c73fd406/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/lirc-tools/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_LIRC_TOOLS
 	bool "lirc-tools"
 	depends on BR2_USE_MMU # fork()
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	help
 	  LIRC is a package that supports receiving and sending IR
 	  signals of the most common IR remote controls. It contains a
@@ -13,3 +14,7 @@ config BR2_PACKAGE_LIRC_TOOLS
 	  enable the kernel drivers to support your hardware.
 
 	  http://www.lirc.org/
+
+comment "lirc-tools needs a toolchain w/ threads"
+	depends on BR2_USE_MMU
+	depends on !BR2_TOOLCHAIN_HAS_THREADS