package/thttpd: add libxcrypt optional dependency

Fix the following build failure raised since bump of glibc to version
2.39 in commit b5680f53d60acf8ff6010082f873438a39bd5d97:

/home/autobuild/autobuild/instance-14/output-1/host/lib/gcc/arm-buildroot-linux-gnueabi/12.3.0/../../../../arm-buildroot-linux-gnueabi/bin/ld: libhttpd.o: in function `auth_check2':
libhttpd.c:(.text+0x3d50): undefined reference to `crypt'

Fixes: b5680f53d60acf8ff6010082f873438a39bd5d97
 - http://autobuild.buildroot.org/results/bfb8a115edf71b1852cc8585c00eb9f0e801a955

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/thttpd/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_THTTPD
 	bool "thttpd"
 	depends on BR2_USE_MMU # fork()
+	select BR2_PACKAGE_LIBXCRYPT if BR2_TOOLCHAIN_USES_GLIBC
 	help
 	  thttpd is a simple, small, portable, fast, and secure HTTP
 	  server

package/thttpd/thttpd.mk

@@ -12,6 +12,10 @@ THTTPD_CPE_ID_VENDOR = acme
 
 THTTPD_MAKE = $(MAKE1)
 
+ifeq ($(BR2_PACKAGE_LIBXCRYPT),y)
+THTTPD_DEPENDENCIES += libxcrypt
+endif
+
 define THTTPD_INSTALL_TARGET_CMDS
 	$(INSTALL) -D -m 0755 $(@D)/thttpd $(TARGET_DIR)/usr/sbin/thttpd
 	$(INSTALL) -D -m 0755 $(@D)/extras/htpasswd $(TARGET_DIR)/usr/bin/htpasswd