sparc: needs -fPIC

Pinted out by Thomas Petazzoni.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/Makefile b/Makefile
index 0a5f869..c756dfe 100644
--- a/Makefile
+++ b/Makefile
@@ -178,7 +178,7 @@
 # SUBARCH is subsequently ignored.
 
 ifneq ($(CROSS_COMPILE),)
-SUBARCH := $(shell echo $(CROSS_COMPILE) | cut -d- -f1)
+SUBARCH := $(shell echo $(CROSS_COMPILE) | cut -d- -f1 | sed 's:^.*/::g')
 else
 SUBARCH := $(shell uname -m)
 endif