diff --git a/configure.ac b/configure.ac
index 44e901a5..ac130181 100644
--- a/configure.ac
+++ b/configure.ac
@@ -63,10 +63,44 @@ LIBZMQ_CHECK_ENABLE_DEBUG
 # Check wheter to enable code coverage
 LIBZMQ_WITH_GCOV
 
-# Checks for libraries
-AC_CHECK_LIB([pthread], [pthread_create])
-AC_CHECK_LIB([rt], [clock_gettime])
-AC_CHECK_LIB([sodium], [sodium_init],,AC_MSG_WARN(libsodium is needed for CURVE security))
+# Allow libsodium to be installed in a custom path:
+
+AC_ARG_WITH([libsodium],
+            [AS_HELP_STRING([--with-libsodium],
+                            [Specify libsodium prefix])],
+            [zmq_search_libsodium="yes"],
+            [])
+
+if test "x$zmq_search_libsodium" = "xyes"; then
+    if test -r "${with_libsodium}/include/sodium.h"; then
+        CPPFLAGS="-I${with_libsodium}/include ${CPPFLAGS}"
+        LDFLAGS="-L${with_libsodium}/lib ${LDFLAGS}"
+    fi
+fi
+
+AC_ARG_WITH([libsodium-include-dir],
+            [AS_HELP_STRING([--with-libsodium-include-dir],
+                            [Specify libsodium include prefix])],
+            [zmq_search_libsodium_include="yes"],
+            [])
+
+if test "x$zmq_search_libsodium_include" = "xyes"; then
+    if test -r "${with_libsodium_include_dir}/sodium.h"; then
+        CPPFLAGS="-I${with_libsodium_include_dir}/include ${CPPFLAGS}"
+    fi
+fi
+
+AC_ARG_WITH([libsodium_lib_dir],
+            [AS_HELP_STRING([--with-libsodium-lib-dir],
+                            [Specify libsodium library prefix])],
+            [zmq_search_libsodium_lib="yes"],
+            [])
+
+if test "x$zmq_search_libsodium_lib" = "xyes"; then
+    if test -r "${with_libsodium_lib_dir}/libsodium.{a|so|dylib}"; then
+        LDFLAGS="-L${with_libsodium}/lib ${LDFLAGS}"
+    fi
+fi
 
 # Set pedantic
 libzmq_pedantic="yes"
@@ -122,6 +156,9 @@ case "${host_os}" in
         if test "x$solaris_has_atomic" = "xno"; then
             AC_DEFINE(ZMQ_FORCE_MUTEXES, 1, [Force to use mutexes])
         fi
+        # ssp library is required for libsodium on Solaris-like systems
+        LDFLAGS="-lssp $LDFLAGS"
+        CPPFLAGS="$CPPFLAGS -Wno-long-long"
         ;;
     *freebsd*)
         # Define on FreeBSD to enable all library features
@@ -215,6 +252,11 @@ case "${host_os}" in
         ;;
 esac
 
+# Checks for libraries
+AC_CHECK_LIB([pthread], [pthread_create])
+AC_CHECK_LIB([rt], [clock_gettime])
+AC_CHECK_LIB([sodium], [sodium_init],,AC_MSG_WARN(libsodium is needed for CURVE security))
+
 #
 # Check if the compiler supports -fvisibility=hidden flag. MinGW32 uses __declspec
 #
diff --git a/include/zmq_utils.h b/include/zmq_utils.h
index a40df7e2..4fe8fcd2 100644
--- a/include/zmq_utils.h
+++ b/include/zmq_utils.h
@@ -82,6 +82,12 @@ ZMQ_EXPORT void *zmq_threadstart (zmq_thread_fn* func, void* arg);
 /* Wait for thread to complete then free up resources.                        */
 ZMQ_EXPORT void zmq_threadclose (void* thread);
 
+/* Encode data with Z85 encoding. Returns encoded data                        */
+ZMQ_EXPORT char *zmq_z85_encode (char *dest, uint8_t *data, size_t size);
+
+/* Decode data with Z85 encoding. Returns decoded data                        */
+ZMQ_EXPORT uint8_t *zmq_z85_decode (uint8_t *dest, char *string);
+
 #undef ZMQ_EXPORT
 
 #ifdef __cplusplus
diff --git a/tools/curve_keygen.c b/tools/curve_keygen.c
index c18c4621..eb1f0bbb 100644
--- a/tools/curve_keygen.c
+++ b/tools/curve_keygen.c
@@ -25,6 +25,7 @@
 */
 
 #include <assert.h>
+#include <platform.hpp>
 #include <zmq_utils.h>
 #ifdef HAVE_LIBSODIUM
 #   include <sodium.h>