Fix the `sizes` regressions in Linux GN.

base/allocator/BUILD.gn

Index: base/allocator/BUILD.gn
diff --git a/base/allocator/BUILD.gn b/base/allocator/BUILD.gn
index 470f36328b33967576cc873a0f8766697394f9cf..04409d3948751200da848a94ff91a7e50d90b448 100644
--- a/base/allocator/BUILD.gn
+++ b/base/allocator/BUILD.gn
@@ -99,7 +99,10 @@ if (is_win) {
 
 if (use_allocator == "tcmalloc") {
   # tcmalloc currently won't compile on Android.
-  source_set("tcmalloc") {
+  # TODO(crbug.com/559766) this should be a source_set but
+  # there are static initializers that get accidentally linked
+  # into chrome from vdso_support.cc that need to be addressed first.
+  static_library("tcmalloc") {
     tcmalloc_dir = "//third_party/tcmalloc/chromium"
 
     # Don't check tcmalloc's includes. These files include various files like