GN: Add back -fPIC for a few things

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 07ac124fa239c41aabd04cf726faac77ed7414db..346059763e2ab5072efac0a9156fc4e823dd6dc2 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -299,6 +299,17 @@ config("compiler") {
     ]
   }
 
+  # We need -fPIC:
+  # 1. On ARM and MIPS for tcmalloc.
+  # 2. On Android.
+  # 3. When using the sanitizers.
+  # Otherwise there is a performance hit, in particular on ia32.
+  if (is_android || is_asan || is_lsan || is_msan || is_tsan ||
+      (is_linux && (current_cpu == "arm" || current_cpu == "mipsel"))) {
+    cflags += [ "-fPIC" ]
+    ldflags += [ "-fPIC" ]
+  }
+
   # Linux-specific compiler flags setup.
   # ------------------------------------
   if (is_linux) {