Remove Windows-related GN build configuration

build/secondary/third_party/libjpeg_turbo/BUILD.gn

Index: build/secondary/third_party/libjpeg_turbo/BUILD.gn
diff --git a/build/secondary/third_party/libjpeg_turbo/BUILD.gn b/build/secondary/third_party/libjpeg_turbo/BUILD.gn
index bf35d07eaa8c1ccff6cc63b29a97a74fd66900e9..7bb83d1ebb218bf7301be0adaa7ce1611bf0dade 100644
--- a/build/secondary/third_party/libjpeg_turbo/BUILD.gn
+++ b/build/secondary/third_party/libjpeg_turbo/BUILD.gn
@@ -73,15 +73,7 @@ if (current_cpu == "x86" || current_cpu == "x64") {
       defines += [ "__x86_64__" ]
     }
 
-    if (is_win) {
-      defines += [ "MSVC" ]
-      include_dirs = [ "win" ]
-      if (current_cpu == "x86") {
-        defines += [ "WIN32" ]
-      } else {
-        defines += [ "WIN64" ]
-      }
-    } else if (is_mac) {
+    if (is_mac) {
       defines += [ "MACHO" ]
       include_dirs = [ "mac" ]
     } else if (is_linux || is_android) {
@@ -99,9 +91,6 @@ source_set("simd") {
     sources = [
       "simd/jsimd_i386.c",
     ]
-    if (is_win) {
-      cflags = [ "/wd4245" ]
-    }
   } else if (current_cpu == "x64") {
     deps = [
       ":simd_asm",