- remove -fno-builtin which is a gcc-only option. I was getting no

compile warnings with or without it on Linux, so it seems no longer
  necessary.  It may have been introduced to cope with the fabs symbol
  conflict, which was already removed in rev1.3 of fpu_etc.c.

bochs/fpu/Makefile-C

@@ -13,7 +13,7 @@ CFLAGS	= -D__KERNEL__ -I$(LOCDIR) -I$(TOPDIR)/include -Wall -Wstrict-prototypes
 #DEBUG	= -DDEBUGGING
 DEBUG	=
 PARANOID = -DPARANOID
-CFLAGS	:= $(CFLAGS) $(PARANOID) $(DEBUG) -fno-builtin -DNO_ASSEMBLER \
+CFLAGS	:= $(CFLAGS) $(PARANOID) $(DEBUG) -DNO_ASSEMBLER \
 		$(MATH_EMULATION)
 
 # From 'C' language sources:

bochs/fpu/Makefile.in

@@ -48,8 +48,7 @@ L_TARGET = libfpu.a
 
 BX_INCDIRS = -I.. -I../@INSTRUMENT_DIR@ -I. -I./stubs
 
-FPU_FLAGS = -DUSE_WITH_CPU_SIM $(PARANOID) $(DEBUG) \
-	-fno-builtin -DNO_ASSEMBLER
+FPU_FLAGS = -DUSE_WITH_CPU_SIM $(PARANOID) $(DEBUG) -DNO_ASSEMBLER
 FPU_GLUE_OBJ = wmFPUemu_glue.o
 
 # From 'C' language sources: