diff --git a/tests/libtest/Makefile.am b/tests/libtest/Makefile.am
index e6a58005482338..0603c03e12aa0d 100644
--- a/tests/libtest/Makefile.am
+++ b/tests/libtest/Makefile.am
@@ -71,7 +71,7 @@ if NO_UNDEFINED
 UNDEF = -no-undefined
 endif
 
-libhostname_la_SOURCES = sethostname.c
+libhostname_la_SOURCES = sethostname.c sethostname.h
 
 libhostname_la_LIBADD =
 libhostname_la_DEPENDENCIES =
diff --git a/tests/libtest/sethostname.c b/tests/libtest/sethostname.c
index 9d9fae00bdc13f..3dabb8231ad0bc 100644
--- a/tests/libtest/sethostname.c
+++ b/tests/libtest/sethostname.c
@@ -9,12 +9,12 @@
 
 #include "setup.h"
 
+#include "sethostname.h"
+
 /*
  * we force our own host name, in order to make some tests machine independent
  */
 
-int gethostname(char *name, GETHOSTNAME_TYPE_ARG2 namelen);
-
 int gethostname(char *name, GETHOSTNAME_TYPE_ARG2 namelen)
 {
   const char *force_hostname = getenv("CURL_GETHOSTNAME");
diff --git a/tests/libtest/sethostname.h b/tests/libtest/sethostname.h
new file mode 100644
index 00000000000000..458a8f0cfe7f41
--- /dev/null
+++ b/tests/libtest/sethostname.h
@@ -0,0 +1,25 @@
+/*****************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ */
+
+#if (defined(WIN32) || defined(__SYMBIAN32__)) && !defined(CURL_STATICLIB)
+#  if defined(BUILDING_LIBCURL)
+#    define LIBHOSTNAME_EXTERN  __declspec(dllexport)
+#  else
+#    define LIBHOSTNAME_EXTERN  __declspec(dllimport)
+#  endif
+#else
+#  ifdef CURL_HIDDEN_SYMBOLS
+#    define LIBHOSTNAME_EXTERN CURL_EXTERN_SYMBOL
+#  else
+#    define LIBHOSTNAME_EXTERN
+#  endif
+#endif
+
+LIBHOSTNAME_EXTERN int gethostname(char *name, GETHOSTNAME_TYPE_ARG2 namelen);
+