Fix GCC build

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 84101f43113969182d0e1c985f1de5f7582dc67d..e43b268ee0bdc8840633dcbf8420e1adcf078a7f 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -65,7 +65,7 @@ config("pdfium_config") {
     ]
   }
 
-  if (is_clang) {
+  if (is_posix) {

[Dirk Pranke, 2016/03/11 21:21:30]

This needs to be is_posix || is_clang, since there's also a win clang.

[hashimoto, 2016/03/14 06:11:31]

I know nothing about win clang, but isn't it supposed be compatible with MSVC
thus covered by the "if (is_win)" above?

[hashimoto, 2016/03/15 05:43:00]

Thanks for the clarification, done.

     # TODO(thestig): Fix all instances, remove this, pdfium:29
     cflags += [ "-Wno-sign-compare" ]
   }
@@ -350,7 +350,11 @@ static_library("fpdfapi") {
     "core/src/fpdfapi/fpdf_render/fpdf_render_text.cpp",
     "core/src/fpdfapi/fpdf_render/render_int.h",
   ]
-  configs += [ ":pdfium_config" ]
+  configs -= [ "//build/config/compiler:chromium_code" ]

[Tom Sepez, 2016/03/14 16:46:54]

Can we just fix the underlying code itself?

+  configs += [
+    ":pdfium_config",
+    "//build/config/compiler:no_chromium_code",
+  ]
 }
 
 static_library("fpdftext") {