8343452: Incorrect WINDOWS build variable is used in macroAssembler_x86.cpp

Reviewed-by: kvn, chagedorn, jwaters

Author: theoweidmannoracle

src/hotspot/cpu/x86/macroAssembler_x86.cpp

@@ -4092,7 +4092,7 @@ RegSet MacroAssembler::call_clobbered_gp_registers() {
   RegSet regs;
 #ifdef _LP64
   regs += RegSet::of(rax, rcx, rdx);
-#ifndef WINDOWS
+#ifndef _WINDOWS
   regs += RegSet::of(rsi, rdi);
 #endif
   regs += RegSet::range(r8, r11);
@@ -4109,7 +4109,7 @@ RegSet MacroAssembler::call_clobbered_gp_registers() {
 
 XMMRegSet MacroAssembler::call_clobbered_xmm_registers() {
   int num_xmm_registers = XMMRegister::available_xmm_registers();
-#if defined(WINDOWS) && defined(_LP64)
+#if defined(_WINDOWS) && defined(_LP64)
   XMMRegSet result = XMMRegSet::range(xmm0, xmm5);
   if (num_xmm_registers > 16) {
      result += XMMRegSet::range(xmm16, as_XMMRegister(num_xmm_registers - 1));