build: libhostname linkage adjustments followup

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 =

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");

tests/libtest/sethostname.h

+/*****************************************************************************
+ *                                  _   _ ____  _
+ *  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);
+