Revert of Mojo: Eliminate duplicate C API symbols

mojo/edk/embedder/BUILD.gn

Index: mojo/edk/embedder/BUILD.gn
diff --git a/mojo/edk/embedder/BUILD.gn b/mojo/edk/embedder/BUILD.gn
index 529aea3b4913b4db2b140a36abdcd0707185c844..e822b196ceb92fc30796602329c7e8fa1412a474 100644
--- a/mojo/edk/embedder/BUILD.gn
+++ b/mojo/edk/embedder/BUILD.gn
@@ -37,7 +37,6 @@
     "embedder.h",
     "embedder_internal.h",
     "entrypoints.cc",
-    "entrypoints.h",
 
     # Test-only code:
     # TODO(vtl): It's a little unfortunate that these end up in the same
@@ -47,7 +46,12 @@
     "test_embedder.h",
   ]
 
-  defines = [ "MOJO_SYSTEM_IMPL_IMPLEMENTATION" ]
+  defines = [
+    "MOJO_SYSTEM_IMPL_IMPLEMENTATION",
+    "MOJO_SYSTEM_IMPLEMENTATION",
+  ]
+
+  configs += [ "//mojo/edk/system:system_config" ]
 
   public_deps = [
     ":delegates",
@@ -94,6 +98,8 @@
 
   defines = [ "MOJO_SYSTEM_IMPL_IMPLEMENTATION" ]
 
+  configs += [ "//mojo/edk/system:system_config" ]
+
   public_deps = [
     "//mojo/public/cpp/system",
   ]
@@ -125,6 +131,8 @@
 
   defines = [ "MOJO_SYSTEM_IMPL_IMPLEMENTATION" ]
 
+  configs += [ "//mojo/edk/system:system_config" ]
+
   public_deps = [
     "//mojo/public/cpp/system",
   ]