iverilog: Allow the user to specify the location of VPI modules.

Make it explicit in the manual that a path can be supplied with the -m
option, and when it is, search for a SFT file there, not in the base
directory.

driver/iverilog.man.in

@@ -190,9 +190,13 @@ prefixed by "I " and other files are prefixed by "M ".
 .B -m\fImodule\fP
 Add this module to the list of VPI modules to be loaded by the
 simulation. Many modules can be specified, and all will be loaded, in
-the order specified. The system module is implicit and always included.
-If a System Function Table file (<module>.sft) exists for the module it
-will be loaded automatically.
+the order specified. The system module is implicit and always included
+(and loaded last). If a System Function Table file (<module>.sft)
+exists for the module it will be loaded automatically.
+
+If the specified name includes at least one directory character, it is
+assumed to be prefixed by the path to the module, otherwise the module
+is assumed to be located in the \fIiverilog\fP base directory.
 .TP 8
 .B -N\fIpath\fP
 This is used for debugging the compiler proper. Dump the final netlist

driver/main.c

@@ -864,7 +864,14 @@ static void add_sft_file(const char *module)
       char *file;
 
       file = (char *) malloc(strlen(base)+1+strlen(module)+4+1);
-      sprintf(file, "%s%c%s.sft", base, sep, module);
+	// If the module name has at least one directory character
+	// in it, assume it includes the path, otherwise look in
+	// the base directory.
+      if (strchr(module, sep))
+	    sprintf(file, "%s.sft", module);
+      else
+	    sprintf(file, "%s%c%s.sft", base, sep, module);
+
       if (access(file, R_OK) == 0)
             fprintf(iconfig_file, "sys_func:%s\n", file);
       free(file);