Fix ARMv6 Linux cross-build

third_party/tcmalloc/BUILD.gn

 # Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 config("internal_config") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
   cflags = [
     "-Wall",
     "-Wextra",
     "-Wno-missing-field-initializers",
@@ skipping 14 matching lines @@
     "-fno-builtin-calloc",
     "-fno-builtin-cfree",
     "-fno-builtin-memalign",
     "-fno-builtin-posix_memalign",
     "-fno-builtin-valloc",
     "-fno-builtin-pvalloc",
   ]
   if (is_clang) {
     cflags += [ "-Wno-unused-const-variable" ]
   }
+  if (current_cpu == "arm" && !is_clang) {
+    cflags += [ "-Wno-psabi" ]
+  }
 }
 
 config("link_config") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
   ldflags = [
     # Don't let linker rip this symbol out, otherwise the heap&cpu
     # profilers will not initialize properly on startup.
     "-Wl,-uIsHeapProfilerRunning,-uProfilerStart",
   ]
 }
@@ skipping 72 matching lines @@
                                   "gperftools/src/base/thread_lister.h",
                                   "gperftools/src/profile-handler.cc",
                                   "gperftools/src/profile-handler.h",
                                   "gperftools/src/profiledata.cc",
                                   "gperftools/src/profiledata.h",
                                   "gperftools/src/profiler.cc",
                                 ])
 
   sources = tcmalloc_sources_list.sources
 }