configure, pc-bios/s390-ccw: pass cross CFLAGS correctly

QEMU_CFLAGS is not available in pc-bios/s390-ccw/netboot.mak, but the Makefile
needs to access the flags passed to the configure script for the s390x
cross compiler.  Fix everything and rename QEMU_CFLAGS to EXTRA_CFLAGS for
consistency with tests/tcg.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -2290,6 +2290,7 @@ if test -n "$target_cc" && test "$softmmu" = yes; then
     config_mak=pc-bios/s390-ccw/config-host.mak
     echo "# Automatically generated by configure - do not modify" > $config_mak
     echo "SRC_PATH=$source_path/pc-bios/s390-ccw" >> $config_mak
+    echo "EXTRA_CFLAGS=$target_cflags" >> $config_mak
     write_target_makefile >> $config_mak
     # SLOF is required for building the s390-ccw firmware on s390x,
     # since it is using the libnet code from SLOF for network booting.

pc-bios/s390-ccw/Makefile

@@ -18,11 +18,11 @@ $(call set-vpath, $(SRC_PATH))
 QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
 
 %.o: %.c
-	$(call quiet-command,$(CC) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) \
+	$(call quiet-command,$(CC) $(EXTRA_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) \
 	       -c -o $@ $<,"CC","$(TARGET_DIR)$@")
 
 %.o: %.S
-	$(call quiet-command,$(CCAS) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) \
+	$(call quiet-command,$(CCAS) $(EXTRA_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) \
 	       -c -o $@ $<,"CCAS","$(TARGET_DIR)$@")
 
 .PHONY : all clean build-all
@@ -30,14 +30,14 @@ QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
 OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o \
 	  virtio.o virtio-scsi.o virtio-blkdev.o libc.o cio.o dasd-ipl.o
 
-QEMU_CFLAGS := -Wall $(filter -W%, $(QEMU_CFLAGS))
-QEMU_CFLAGS += $(call cc-option,-Werror $(QEMU_CFLAGS),-Wno-stringop-overflow)
-QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -fno-common -fPIE
-QEMU_CFLAGS += -fwrapv -fno-strict-aliasing -fno-asynchronous-unwind-tables
-QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
-QEMU_CFLAGS += -msoft-float
-QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS),-march=z900,-march=z10)
-QEMU_CFLAGS += -std=gnu99
+EXTRA_CFLAGS := $(EXTRA_CFLAGS) -Wall
+EXTRA_CFLAGS += $(call cc-option,-Werror $(EXTRA_CFLAGS),-Wno-stringop-overflow)
+EXTRA_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -fno-common -fPIE
+EXTRA_CFLAGS += -fwrapv -fno-strict-aliasing -fno-asynchronous-unwind-tables
+EXTRA_CFLAGS += $(call cc-option, $(EXTRA_CFLAGS), -fno-stack-protector)
+EXTRA_CFLAGS += -msoft-float
+EXTRA_CFLAGS += $(call cc-option, $(EXTRA_CFLAGS),-march=z900,-march=z10)
+EXTRA_CFLAGS += -std=gnu99
 LDFLAGS += -Wl,-pie -nostdlib
 
 build-all: s390-ccw.img s390-netboot.img

pc-bios/s390-ccw/netboot.mak

@@ -8,7 +8,7 @@ LIBNET_INC := -I$(SLOF_DIR)/lib/libnet
 
 NETLDFLAGS := $(LDFLAGS) -Wl,-Ttext=0x7800000
 
-$(NETOBJS): QEMU_CFLAGS += $(LIBC_INC) $(LIBNET_INC)
+$(NETOBJS): EXTRA_CFLAGS += $(LIBC_INC) $(LIBNET_INC)
 
 s390-netboot.elf: $(NETOBJS) libnet.a libc.a
 	$(call quiet-command,$(CC) $(NETLDFLAGS) -o $@ $^,"BUILD","$(TARGET_DIR)$@")
@@ -18,7 +18,7 @@ s390-netboot.img: s390-netboot.elf
 
 # libc files:
 
-LIBC_CFLAGS = $(QEMU_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
+LIBC_CFLAGS = $(EXTRA_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
 	      -MMD -MP -MT $@ -MF $(@:%.o=%.d)
 
 CTYPE_OBJS = isdigit.o isxdigit.o toupper.o
@@ -52,7 +52,7 @@ libc.a: $(LIBCOBJS)
 
 LIBNETOBJS := args.o dhcp.o dns.o icmpv6.o ipv6.o tcp.o udp.o bootp.o \
 	      dhcpv6.o ethernet.o ipv4.o ndp.o tftp.o pxelinux.o
-LIBNETCFLAGS = $(QEMU_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
+LIBNETCFLAGS = $(EXTRA_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
 	       -DDHCPARCH=0x1F -MMD -MP -MT $@ -MF $(@:%.o=%.d)
 
 %.o : $(SLOF_DIR)/lib/libnet/%.c