dump.c: Fix broken c++ compilations in

Commit bce5eba broke c++ compilations
because a goto now crosses declarations with initialization.

This commit merely separates the declarations from their initialization,
and moves the declarations to before the goto.

The alternative could just as easily have been to move the goto to after
the initialization, but the initialization would then be (a bit of)
extra work, and more importantly, that would break the code flow of
immediately using the initialized values.

Author: khwilliamson

dump.c

@@ -1126,6 +1126,8 @@ S_get_sv_from_pad(pTHX_ const OP *o, PADOFFSET po, CV *rootcv)
         return NULL;
 
     CV *cv = NULL;
+    int n;
+    OP *oproot;
 
     if (rootcv) {
         cv = rootcv;
@@ -1138,8 +1140,8 @@ S_get_sv_from_pad(pTHX_ const OP *o, PADOFFSET po, CV *rootcv)
      * stack. Limit the number of hops, in case there is some sort of
      * loop or other weirdness.
      */
-    int n = 100;
-    OP *oproot = (OP*)o;
+    n = 100;
+    oproot = (OP*)o;
     while (1) {
         if (--n <= 0)
             return NULL;