package/coremark-pro: add dependency on threads

Coremark-pro requires threads so add a depends on
BR2_TOOLCHAIN_HAS_THREADS.

Fixes:
- http://autobuild.buildroot.net/results/ab574485a7856fcf5cd643c154c44b4bfcb34a97/

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/coremark-pro/Config.in

@@ -1,8 +1,13 @@
 config BR2_PACKAGE_COREMARK_PRO
 	bool "coremark-pro"
 	depends on BR2_USE_MMU # perl uses fork()
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_PERL
 	help
 	  CoreMark-PRO is a comprehensive, advanced processor benchmark.
 
 	  https://www.eembc.org/coremark-pro/
+
+comment "coremark-pro needs a toolchain w/ threads"
+	depends on BR2_USE_MMU
+	depends on !BR2_TOOLCHAIN_HAS_THREADS