attr: clarify license info

As pointed out by Thomas Petazzoni in his review.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/attr/attr.mk

@@ -9,7 +9,7 @@ ATTR_SOURCE = attr-$(ATTR_VERSION).src.tar.gz
 ATTR_SITE = http://download.savannah.gnu.org/releases/attr
 ATTR_INSTALL_STAGING = YES
 ATTR_CONF_OPT = --enable-gettext=no
-ATTR_LICENSE = GPLv2+ LGPGv2.1+
+ATTR_LICENSE = GPLv2+ (programs), LGPLv2.1+ (libraries)
 ATTR_LICENSE_FILES = doc/COPYING doc/COPYING.LGPL
 
 # While the configuration system uses autoconf, the Makefiles are