adduser/addgroup: check username for invalid chars
(by Tito <farmatito AT tiscali.it>). +129 bytes when enabled.
diff --git a/libbb/Kbuild b/libbb/Kbuild
index 654722c..5740d92 100644
--- a/libbb/Kbuild
+++ b/libbb/Kbuild
@@ -122,6 +122,7 @@
lib-$(CONFIG_SELINUX) += selinux_common.o
lib-$(CONFIG_HWCLOCK) += rtc.o
lib-$(CONFIG_RTCWAKE) += rtc.o
+lib-$(CONFIG_FEATURE_CHECK_NAMES) += die_if_bad_username.o
# We shouldn't build xregcomp.c if we don't need it - this ensures we don't
# require regex.h to be in the include dir even if we don't need it thereby