fix #285 .spiceinit cannot be read in from home directory

reported by Craggan in bug report #285
http://sourceforge.net/p/ngspice/bugs/285/

src/sharedspice.c

@@ -610,7 +610,7 @@ ngSpice_Init(SendChar* printfcn, SendStat* statusfcn, ControlledExit* ngspiceexi
         struct passwd *pw;
         pw = getpwuid(getuid());
 
-        s = tprintf("%s%s", pw->pw_dir, INITSTR);
+        s = tprintf("%s" DIR_PATHSEP "%s", pw->pw_dir, INITSTR);
 
         if (access(s, 0) == 0)
             inp_source(s);

src/tclspice.c

@@ -2522,7 +2522,7 @@ Spice_Init(Tcl_Interp *interp)
             struct passwd *pw;
             pw = getpwuid(getuid());
 
-            s = tprintf("%s%s", pw->pw_dir, INITSTR);
+            s = tprintf("%s" DIR_PATHSEP "%s", pw->pw_dir, INITSTR);
 
             if (access(s, 0) == 0)
                 inp_source(s);