opkg: ignore empty fields in package lists

This is to work around issues with package list generators creating
empty fields in some environments.

Based on a patch by Paul Selkrik <pselkrik@isc.org>
Signed-off-by: Steven Barth <steven@midlink.org>

SVN-Revision: 38390

package/system/opkg/Makefile

@@ -11,7 +11,7 @@ include $(INCLUDE_DIR)/version.mk
 PKG_NAME:=opkg
 PKG_REV:=618
 PKG_VERSION:=$(PKG_REV)
-PKG_RELEASE:=5
+PKG_RELEASE:=6
 
 PKG_SOURCE_PROTO:=svn
 PKG_SOURCE_VERSION:=$(PKG_REV)

package/system/opkg/patches/080-suppress-blank-package-fields.patch

@@ -0,0 +1,16 @@
+--- a/libopkg/parse_util.c
++++ b/libopkg/parse_util.c
+@@ -35,7 +35,12 @@ is_field(const char *type, const char *l
+ char *
+ parse_simple(const char *type, const char *line)
+ {
+-	return trim_xstrdup(line + strlen(type) + 1);
++	char *field = trim_xstrdup(line + strlen(type) + 1);
++	if (strlen(field) == 0) {
++		free(field);
++		return NULL;
++	}
++	return field;
+ }
+ 
+ /*