Add basic errno support.

Needed for hash table support; probably useful in a lot of other
places as well.

Signed-off-by: Wolfgang Denk <wd@denx.de>

lib/Makefile

@@ -37,6 +37,7 @@ COBJS-y += crc32.o
 COBJS-y += ctype.o
 COBJS-y += display_options.o
 COBJS-y += div64.o
+COBJS-y += errno.o
 COBJS-$(CONFIG_GZIP) += gunzip.o
 COBJS-$(CONFIG_LMB) += lmb.o
 COBJS-y += ldiv.o

lib/errno.c

@@ -0,0 +1 @@
+int errno = 0;