diff --git a/Makefile b/Makefile
index 022731d8b..4c1335582 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,8 @@
 #   USE_TPROXY           : enable transparent proxy. Automatic.
 #   USE_LINUX_TPROXY     : enable full transparent proxy (need kernel patch).
 #   USE_LINUX_SPLICE     : enable kernel 2.6 splicing (broken on old kernels)
+#   USE_LIBCRYPT         : enable crypted passwords using -lcrypt
+#   USE_CRYPT_H          : set it if your system requires including crypt.h
 #
 # Options can be forced by specifying "USE_xxx=1" or can be disabled by using
 # "USE_xxx=" (empty string).
@@ -208,6 +210,8 @@ ifeq ($(TARGET),solaris)
   TARGET_CFLAGS  = -fomit-frame-pointer -DFD_SETSIZE=65536 -D_REENTRANT
   TARGET_LDFLAGS = -lnsl -lsocket
   USE_TPROXY     = implicit
+  USE_LIBCRYPT    = implicit
+  USE_CRYPT_H     = implicit
 else
 ifeq ($(TARGET),freebsd)
   # This is for FreeBSD
@@ -336,6 +340,11 @@ BUILD_OPTIONS   += $(call ignore_implicit,USE_LIBCRYPT)
 OPTIONS_LDFLAGS += -lcrypt
 endif
 
+ifneq ($(USE_CRYPT_H),)
+OPTIONS_CFLAGS  += -DNEED_CRYPT_H
+BUILD_OPTIONS   += $(call ignore_implicit,USE_CRYPT_H)
+endif
+
 ifneq ($(USE_POLL),)
 OPTIONS_CFLAGS += -DENABLE_POLL
 OPTIONS_OBJS   += src/ev_poll.o
diff --git a/src/auth.c b/src/auth.c
index 93af8d68c..8ae485864 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -10,7 +10,15 @@
  *
  */
 
-#define _XOPEN_SOURCE 500
+#ifdef CONFIG_HAP_CRYPT
+/* This is to have crypt() defined on Linux */
+#define _GNU_SOURCE
+
+#ifdef NEED_CRYPT_H
+/* some platforms such as Solaris need this */
+#include <crypt.h>
+#endif
+#endif /* CONFIG_HAP_CRYPT */
 
 #include <stdio.h>
 #include <stdlib.h>