Change names in OpTYPE_set() to avoid possible collisions

This uses the PERL_UNIQUE_NAME() macro created in the previous commit to
get unique names for variables in macro expansions.

Suppose you have

    #define foo STMT_START { ... } STMT_END

block, and have a variable 'bar' declared in it.  By first saying

    #define bar PERL_UNIQUE_NAME(bar)

'bar' will be replaced in the expansion of 'foo' by a unique value.

It is your responsibility to not have two 'bar' symbols in the same
program.  But if you forget, you will be warned by the compiler that
'bar' is redefined, so you can fix it
.

Author: khwilliamson

op.h

@@ -64,12 +64,14 @@ typedef PERL_BITFIELD16 Optype;
     U8		op_private;
 #endif
 
+#define o1_     PERL_UNIQUE_NAME(o)
+#define type1_  PERL_UNIQUE_NAME(type)
 #define OpTYPE_set(o,type)                      \
     STMT_START {                                \
-        OP *o_ = (OP *)o;                       \
-        OPCODE type_ = type;                    \
-        o_->op_type = type_;                    \
-        o_->op_ppaddr = PL_ppaddr[type_];       \
+        OP *o1_ = (OP *)o;                      \
+        OPCODE type1_ = type;                   \
+        o1_->op_type = type1_;                  \
+        o1_->op_ppaddr = PL_ppaddr[type1_];     \
     } STMT_END
 
 /* If op_type:9 is changed to :10, also change cx_pusheval()