Merge branch 'test/spin_interface'; adds a (so far unused) %interface keyword to Spin2

Author: totalspectrum

frontends/lexer.c

@@ -2103,6 +2103,7 @@ struct reservedword {
     { "%if", SP_ASM_IF },
     { "if", SP_IF },
     { "ifnot", SP_IFNOT },
+    { "%interface", SP_INTERFACE },
 
     { "long", SP_LONG },
     { "lookdown", SP_LOOKDOWN },

frontends/spin/spin.y

@@ -163,6 +163,7 @@ FixupList(AST *list)
 %token SP_PUB        "PUB"
 %token SP_PRI        "PRI"
 %token SP_OBJ        "OBJ"
+%token SP_INTERFACE  "%INTERFACE"
 %token SP_ASM        "ASM"
 %token SP_ASM_CONST  "ASM_CONST"
 %token SP_ENDASM     "ENDASM"