make sure the added march=skylake-avx512 does not cause problems on Windows

kernel/Makefile

@@ -7,7 +7,15 @@ include $(TOPDIR)/Makefile.system
 
 ifdef TARGET_CORE
 ifeq ($(TARGET_CORE), SKYLAKEX)
-override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE) -march=skylake-avx512
+ override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE) -march=skylake-avx512
+ ifeq ($(OSNAME), CYGWIN_NT)
+  override CFLAGS += -fno-asynchronous-unwind-tables
+ endif
+ ifeq ($(OSNAME), WINNT)
+  ifeq ($(C_COMPILER), GCC)
+   override CFLAGS += -fno-asynchronous-unwind-tables
+  endif
+ endif
 else
 override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE)
 endif