dselect: Use static_cast<> instead of old-style type qualifier cast

Warned-by: g++ -Wcast-qual

debian/changelog

@@ -189,6 +189,7 @@ dpkg (1.20.0) UNRELEASED; urgency=medium
     - dselect: Reorder branches in packagelist::deselect_one_of so that they
       are not duplicated.
     - dselect: Use nullptr instead of NULL.
+    - dselect: Use static_cast<> instead of old-style type qualifier cast.
   * Build system:
     - Bump minimal Perl version to 5.24.1.
     - Add a serial versioning to the m4 files.

dselect/baselist.cc

@@ -64,8 +64,8 @@ void baselist::sigwinchhandler(int) {
 }
 
 static void cu_sigwinch(int, void **argv) {
-  struct sigaction *osigactp= (struct sigaction*)argv[0];
-  sigset_t *oblockedp= (sigset_t*)argv[1];
+  struct sigaction *osigactp = static_cast<struct sigaction *>(argv[0]);
+  sigset_t *oblockedp = static_cast<sigset_t *>(argv[1]);
 
   if (sigaction(SIGWINCH, osigactp, nullptr))
     ohshite(_("failed to restore old SIGWINCH sigact"));

dselect/main.cc

@@ -354,8 +354,8 @@ void cursesoff() {
 }
 
 urqresult urq_list(void) {
-  modstatdb_open((modstatdb_rw)(msdbrw_writeifposs |
-                                msdbrw_available_readonly));
+  modstatdb_open(static_cast<modstatdb_rw>(msdbrw_writeifposs |
+                                           msdbrw_available_readonly));
 
   curseson();
 

dselect/pkglist.cc

@@ -151,8 +151,10 @@ void packagelist::addheading(enum ssavailval ssavail,
 static packagelist *sortpackagelist;
 
 int qsort_compareentries(const void *a, const void *b) {
-  return sortpackagelist->compareentries(*(const struct perpackagestate **)a,
-                                         *(const struct perpackagestate **)b);
+  const struct perpackagestate *pa = *static_cast<const struct perpackagestate * const *>(a);
+  const struct perpackagestate *pb = *static_cast<const struct perpackagestate * const *>(b);
+
+  return sortpackagelist->compareentries(pa, pb);
 }
 
 void packagelist::sortinplace() {