Fix net_unittests targets to pass on iOS using GN.

build/secondary/third_party/nss/BUILD.gn

Index: build/secondary/third_party/nss/BUILD.gn
diff --git a/build/secondary/third_party/nss/BUILD.gn b/build/secondary/third_party/nss/BUILD.gn
index 7b32a04cbf850f9d902011f12cc2466cc6320b0e..2dc414d716f0fe40016b2ebc2260167522bc1916 100644
--- a/build/secondary/third_party/nss/BUILD.gn
+++ b/build/secondary/third_party/nss/BUILD.gn
@@ -474,6 +474,30 @@ if (is_linux) {
     ]
   }
 
+  config("nss_static_config_private") {
+    if (is_clang) {
+      cflags = [
+        # nss doesn"t explicitly cast between different enum types.
+        "-Wno-conversion",
+
+        # nss passes "const char*" through "void*".
+        "-Wno-incompatible-pointer-types",
+
+        # nss prefers `a && b || c` over `(a && b) || c`.
+        "-Wno-logical-op-parentheses",
+
+        # nss doesn"t use exhaustive switches on enums
+        "-Wno-switch",
+
+        # nss has some `unsigned < 0` checks.
+        "-Wno-tautological-compare",
+
+        # nss-urandom-abort.patch removed the only call to rng_systemFromNoise
+        "-Wno-unused-function",
+      ]
+    }
+  }

[Dirk Pranke, 2016/01/29 00:55:39]

why this change?

[sdefresne, 2016/01/29 09:04:44]

I though I explained this in the CL description. Without the change, the
command-line looks like the following on iOS:

... -Wno-unused-function ... -Wall ...

where -Wall comes from //build/config/compiler:no_chromium_code while the
-Wno-unused-function comes from the cflags inlined in the target. This is
because the flags inlined in the targets comes before the one from dependent
config. By moving the flags into a private config, they end up after those
coming from //build/config/compiler:no_chromium_code and we end up with a
command-line that looks like this:

... -Wall ... -Wno-unused-function ...

In general the ordering of the flags would not be a problem, however, -Wall set
-Wunused-function and thus override the -Wno-unused-function from the target
cflags, and cause compilation failure due to the unused rng_systemFromNoise
function.

[sdefresne, 2016/01/29 10:58:21]

Extracted as a separate CL: https://codereview.chromium.org/1644333002

[Dirk Pranke, 2016/01/29 18:59:40]

Ah, right. Sorry for the confusion!

+
   if (is_win && current_cpu == "x86") {
     source_set("nss_static_avx") {
       sources = [
@@ -891,6 +915,7 @@ if (is_linux) {
 
       # nss passes "const char*" through "void*".
       "//build/config/compiler:no_incompatible_pointer_warnings",
+      ":nss_static_config_private",
     ]
     public_configs = [ ":nss_static_config" ]
 
@@ -1183,28 +1208,6 @@ if (is_linux) {
       ]
     }
 
-    if (is_clang) {
-      cflags += [
-        # nss doesn"t explicitly cast between different enum types.
-        "-Wno-conversion",
-
-        # nss passes "const char*" through "void*".
-        "-Wno-incompatible-pointer-types",
-
-        # nss prefers `a && b || c` over `(a && b) || c`.
-        "-Wno-logical-op-parentheses",
-
-        # nss doesn"t use exhaustive switches on enums
-        "-Wno-switch",
-
-        # nss has some `unsigned < 0` checks.
-        "-Wno-tautological-compare",
-
-        # nss-urandom-abort.patch removed the only call to rng_systemFromNoise
-        "-Wno-unused-function",
-      ]
-    }
-
     public_deps = [
       ":nspr",
     ]