linux-syscall-support: add package (#2723)

* linux-syscall-support: add package

* improve include

packages/l/linux-syscall-support/xmake.lua

@@ -0,0 +1,15 @@
+package("linux-syscall-support")
+    set_homepage("https://chromium.googlesource.com/linux-syscall-support")
+    set_description("Linux Syscall Support provides a header file that can be included into your application whenever you need to make direct system calls.")
+    set_license("BSD-3-Clause")
+
+    add_urls("https://chromium.googlesource.com/linux-syscall-support.git")
+    add_versions("v2022.10.12", "9719c1e1e676814c456b55f5f070eabad6709d31")
+
+    on_install("linux", function (package)
+        os.cp("linux_syscall_support.h", package:installdir("include/lss"))
+    end)
+
+    on_test(function (package)
+        assert(package:has_cfuncs("sys_open", {includes = "lss/linux_syscall_support.h"}))
+    end)