sparc: needs -fPIC

Pinted out by Thomas Petazzoni.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

arch/sparc/Makefile

@@ -0,0 +1,11 @@
+# When building a library, even intra-library references,
+# such as from find_applet_by_name() to applet_names[],
+# don't work with -fpic on sparc, needs -fPIC.
+# Don't know why it fails in this case but works when
+# a binary is being built.
+#
+# (if is superfluous, ARCH_FPIC is only used by library build, but it
+# demonstrates the point: non-pic binary does not need it)
+ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
+ARCH_FPIC = -fPIC
+endif