Remove non-source sources from binary targets

No behavior changes.

* Remove nacl_random_private since it's unused.
* Remove "None" and "private_blockhook" sources form nacl_sys_private.
  gn used to ignore these files since they didn't match any known
  extension, but now gn errors out on these files, so they must be
  removed.  See https://bugs.chromium.org/p/gn/issues/detail?id=77.

BUG=chromium:964411
R=thakis

NOTRY=true

Change-Id: Iee2e1cd8e008cc7986e9ac91a30e618a96268dfa
Reviewed-on: https://chromium-review.googlesource.com/c/native_client/src/native_client/+/1617981
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Mark Seaborn <mseaborn@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
diff --git a/src/untrusted/nacl/BUILD.gn b/src/untrusted/nacl/BUILD.gn
index aaa4c90..ff5dbfd 100644
--- a/src/untrusted/nacl/BUILD.gn
+++ b/src/untrusted/nacl/BUILD.gn
@@ -19,21 +19,6 @@
     "//build/config/nacl:nacl_base",
   ]
 }
-static_library("nacl_random_private") {
-  cflags_c = []
-  sources = [
-    "irt_random",
-  ]
-
-  if (current_cpu == "pnacl") {
-    cflags_c += [
-      "-Wno-self-assign",
-    ]
-  }
-  deps = [
-    "//build/config/nacl:nacl_base",
-  ]
-}
 static_library("nacl_sys_private") {
   cflags_c = []
   sources = [
@@ -41,13 +26,6 @@
     "sysbrk.c",
   ]
 
-  if (current_os != "glibc") {
-    sources += [
-      "None",
-      "private_blockhook",
-    ]
-  }
-
   if (current_cpu == "pnacl") {
     cflags_c += [
       "-Wno-self-assign",