GTKWave (fstapi.c) needs realpath() so check for it

config.h.in

@@ -1,7 +1,7 @@
 #ifndef IVL_config_H                                           /* -*- c++ -*- */
 #define IVL_config_H
 /*
- * Copyright (c) 2001-2014 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001-2015 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -55,6 +55,7 @@
 # undef HAVE_FSEEKO
 /* And this is needed by the fst files (copied from GTKWave). */
 # undef HAVE_LIBPTHREAD
+# undef HAVE_REALPATH
 
 /*
  * Define this if you want to compile vvp with memory freeing and

configure.in

@@ -242,6 +242,9 @@ case "${host}" in
 esac
 AC_SUBST(file64_support)
 
+# fstapi.c (from GTKWave) needs this define.
+AC_CHECK_FUNCS(realpath)
+
 # Check that these functions exist. They are mostly C99
 # functions that older compilers may not yet support.
 AC_CHECK_FUNCS(fopen64)

vpi/fstapi.c

@@ -279,7 +279,6 @@ return(ftruncate(fd, length));
 static char *fstRealpath(const char *path, char *resolved_path)
 {
 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __CYGWIN__ || defined HAVE_REALPATH
-
 #if (defined(__MACH__) && defined(__APPLE__))
 if(!resolved_path)
         {
@@ -297,6 +296,8 @@ if(!resolved_path)
         }
 return(_fullpath(resolved_path, path, PATH_MAX));
 #else
+(void)path;
+(void)resolved_path;
 return(NULL);
 #endif
 #endif