arc: Make sure that libgcc doesn't get included when it doesn't exist yet

For ARC, libgcc is always included, even when -nostdlib is given. This is
related to some small pieces of code that are not always generated by the
compiler; a call to libgcc is used in those cases instead.

During the initial stages of building the toolchain, this is a problem, as
libgcc does not exist yet. The ARC compiler supports -really-nostdlib to
override the default behavior.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

toolchain/uClibc/uclibc.mk

@@ -404,6 +404,17 @@ ifeq ($(BR2_CCACHE),y)
 $(UCLIBC_DIR)/.config: | host-ccache
 endif
 
+# For ARC, libgcc is always included, even when -nostdlib is given. This
+# is related to some small pieces of code that are not always generated
+# by the compiler; a call to libgcc is used in those cases instead.
+#
+# During the initial stages of building the toolchain, this is a problem,
+# as libgcc does not exist yet. The ARC compiler supports -really-nostdlib
+# to override the default behavior.
+ifeq ($(BR2_arc),y)
+REALLY_NOSTDLIB=-really-nostdlib
+endif
+
 $(UCLIBC_DIR)/.configured: $(LINUX_HEADERS_DIR)/.configured $(UCLIBC_DIR)/.config
 	$(Q)$(call MESSAGE,"Installing uClibc headers")
 	$(MAKE1) -C $(UCLIBC_DIR) \
@@ -422,8 +433,8 @@ $(UCLIBC_DIR)/.configured: $(LINUX_HEADERS_DIR)/.configured $(UCLIBC_DIR)/.confi
 		cp -pLR $(LINUX_HEADERS_DIR)/include/* \
 			$(TOOLCHAIN_DIR)/uClibc_dev/usr/include/; \
 	fi
-	$(TARGET_CROSS)gcc -nostdlib -nostartfiles -shared -x c /dev/null -o $(TOOLCHAIN_DIR)/uClibc_dev/usr/lib/libc.so
-	$(TARGET_CROSS)gcc -nostdlib -nostartfiles -shared -x c /dev/null -o $(TOOLCHAIN_DIR)/uClibc_dev/usr/lib/libm.so
+	$(TARGET_CROSS)gcc -nostdlib $(REALLY_NOSTDLIB) -nostartfiles -shared -x c /dev/null -o $(TOOLCHAIN_DIR)/uClibc_dev/usr/lib/libc.so
+	$(TARGET_CROSS)gcc -nostdlib $(REALLY_NOSTDLIB) -nostartfiles -shared -x c /dev/null -o $(TOOLCHAIN_DIR)/uClibc_dev/usr/lib/libm.so
 	cp -pLR $(UCLIBC_DIR)/lib/crt[1in].o $(TOOLCHAIN_DIR)/uClibc_dev/usr/lib/
 	touch $@