[WIDL] Fix a deprecation message and hints on how to build a new scanner and parser

sdk/tools/widl/parser.y

@@ -321,7 +321,7 @@ static typelib_t *current_typelib;
 %right '!' '~' CAST PPTR POS NEG ADDRESSOF tSIZEOF
 %left '.' MEMBERPTR '[' ']'
 
-%error-verbose
+%define parse.error verbose
 
 %%
 

sdk/tools/widl/readme.txt

@@ -0,0 +1,5 @@
+To generate a new scanner and parser run:
+
+flex --header-file=parser.yy.h --outfile=parser.yy.c parser.l
+
+bison --defines=parser.tab.h --name-prefix=parser_ parser.y