Handled the case in which environment variable HOME is not set.

See github issue tracker issue #490.  There were two cases:  When
running without the Tk console, a NULL value was being passed to a
string comparison.  When running with the Tk console, two variables
were not initialized.  Both prolems have been fixed.

tcltk/tkcon.tcl

@@ -249,6 +249,9 @@ proc ::tkcon::Init {} {
 	if {![info exists PRIV(histfile)]} {
 	    set PRIV(histfile)	[file join $env($envHome) $histfile]
 	}
+    } else {
+        set PRIV(rcfile) ""
+        set PRIV(histfile) ""
     }
 
     ## Handle command line arguments before sourcing resource file to

utils/main.c

@@ -988,7 +988,8 @@ mainInitFinal()
 	    }
 	}
 
-        if (getcwd(cwd, 512) == NULL || strcmp(cwd, home) || (RCFileName[0] == '/'))
+        if (getcwd(cwd, 512) == NULL || ((home != NULL) && (strcmp(cwd, home)))
+			|| (RCFileName[0] == '/'))
 	{
 	    /* Read in the .magicrc file from the current directory, if	*/
 	    /* different from HOME.					*/