package/perftest: fix unmet direct dependencies

Since it was iontroduced in commit d4ecefa3ccbe (package/perftest: new
package), perftest was missing the reverse dependency on the kernel
headers version inherited from rdma-core.

In commit 3279d8b9c455 (package/rdma-core: needs NPTL), the dependency
of rdma-core on NTPL was not propagated to its reverse dependencies,
notably perftests.

Fixes:
  - http://autobuild.buildroot.net/results/00c/00ce19a1589c6028ee77c333ed9107e2c8c8d6de
  - d4ecefa3ccbe
  - 3279d8b9c455

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
[yann.morin.1998@free.fr:
  - also add misisng headers dependency
  - expand commit log
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/perftest/Config.in

@@ -20,7 +20,8 @@ config BR2_PACKAGE_PERFTEST_ARCH_SUPPORTS
 config BR2_PACKAGE_PERFTEST
 	bool "perftest"
 	depends on BR2_PACKAGE_PERFTEST_ARCH_SUPPORTS
-	depends on BR2_TOOLCHAIN_HAS_THREADS
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_4 # rdma-core
+	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL # rdma-core
 	depends on !BR2_STATIC_LIBS # rdma-core
 	# musl does not define sysconf(_SC_LEVEL1_DCACHE_LINESIZE)
 	depends on !BR2_TOOLCHAIN_USES_MUSL