diff --git a/Makefile b/Makefile
index c8fd3f5c5..6146d406d 100644
--- a/Makefile
+++ b/Makefile
@@ -92,6 +92,8 @@ CC	:= riscv64-unknown-linux-gnu-gcc
 CXX	:= riscv64-unknown-linux-gnu-g++
 endif
 
+K1OM := $( shell echo | $CC -dM -E - | grep __k1om__ )
+
 #
 # Compile flags
 #
@@ -274,6 +276,9 @@ endif
 ifndef RISCV
 
 ifeq ($(UNAME_M),$(filter $(UNAME_M),x86_64 i686 amd64))
+
+ifeq "$(K1OM)" ""
+
 	# Use all CPU extensions that are available:
 	MK_CFLAGS     += -march=native -mtune=native
 	HOST_CXXFLAGS += -march=native -mtune=native
@@ -287,6 +292,8 @@ ifeq ($(UNAME_M),$(filter $(UNAME_M),x86_64 i686 amd64))
 	#MK_CXXFLAGS += -mssse3
 endif
 
+endif
+
 ifneq '' '$(findstring mingw,$(shell $(CC) -dumpmachine))'
 	# The stack is only 16-byte aligned on Windows, so don't let gcc emit aligned moves.
 	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54412