Raise an error when calling make with MARCHes known to fail

Pre-SSE2 CPUs are not supported as some tests fail (#7185).
Better warn as soon as possible.

Make.inc

@@ -451,6 +451,11 @@ XC_HOST := $(ARCH)$(shell echo $(BUILD_MACHINE) | sed "s/[^-]*\(.*\)$$/\1/")
 MARCH = $(ARCH)
 endif
 
+# Detect common pre-SSE2 MARCH values known not to work
+ifneq ($(findstring $(MARCH),i386 i486 i586 i686 pentium pentium2 pentium3),)
+$(error Pre-SSE2 builds are not supported. To create a generic binary, pass MARCH=pentium4)
+endif
+
 ifneq ($(MARCH),)
 CC += -march=$(MARCH)
 CXX += -march=$(MARCH)