make sure Julia doesn't use x87 math. (JuliaLang#43978)

* use fpmath=sse on 32 bit x86 to prevent 80 bit floats causing double rounding

Co-authored-by: Oscar Smith <oscardssmith@gmail.com>

Make.inc

@@ -874,6 +874,10 @@ ifneq (,$(filter $(ARCH), powerpc64le ppc64le))
 DIST_ARCH:=ppc64le
 endif
 ifeq (1,$(ISX86))
+# on x86 make sure not to use 80 bit math when we want 64 bit math.
+ifeq (32,$BINARY))
+JCFLAGS += -mfpmath=sse
+endif
 DIST_ARCH:=$(BINARY)
 endif
 ifneq (,$(findstring arm,$(ARCH)))