powerpc: change .fixup test to a GCC version test

This was introduced by commit 24461519, but it
fails in a minimal SPL build where the only thing in arch/powerpc/lib is
cache.c, which apparently doesn't generate any fixup records.

The problem is reported to occur with GCC 3.x, so insist on GCC 4.0 or newer.
Patterned after checkthumb as suggested by Tom Rini.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Peter Tyser <ptyser@xes-inc.com>
Cc: Tom Rini <trini@ti.com>
--
v2: test gcc version instead of testing nothing

Makefile

@@ -643,6 +643,16 @@ checkthumb:
 		echo '*** Your board is configured for THUMB mode.'; \
 		false; \
 	fi
+
+# GCC 3.x is reported to have problems generating the type of relocation
+# that U-Boot wants.
+# See http://lists.denx.de/pipermail/u-boot/2012-September/135156.html
+checkgcc4:
+	@if test $(call cc-version) -lt 0400; then \
+		echo -n '*** Your GCC is too old, please upgrade to GCC 4.x or newer'; \
+		false; \
+	fi
+
 #
 # Auto-generate the autoconf.mk file (which is included by all makefiles)
 #

arch/powerpc/config.mk

@@ -42,3 +42,8 @@ endif
 ifeq ($(CROSS_COMPILE),powerpc-openbsd-)
 PLATFORM_CPPFLAGS+= -D__PPC__
 endif
+
+# Only test once
+ifneq ($(CONFIG_SPL_BUILD),y)
+ALL-y += checkgcc4
+endif

arch/powerpc/lib/Makefile

@@ -75,12 +75,6 @@ TARGETS += $(LIB)
 all: $(TARGETS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	@if ! $(CROSS_COMPILE)readelf -S $(OBJS) | grep -q '\.fixup.*PROGBITS';\
-	then \
-		echo "ERROR: Your compiler doesn't generate .fixup sections!";\
-		echo "       Upgrade to a recent toolchain."; \
-		exit 1; \
-	fi;
 	$(call cmd_link_o_target, $(OBJS))
 
 $(LIBGCC): $(obj).depend $(LGOBJS)