Fix FTBFS when using -pedantic compiler flag.

I am attaching an incremental git-am ready patch to go on top your Git HEAD,
to fix all sorts of issues and make this conforming C99 with default
options set,
and fix another load of warnings you receive when setting the compiler
to pick the nits,
-pedantic-errors -std=c99 (or c11, c18, c2x).
It changes many void * to uint8_t * to make the "increment by bytes"
explicit.
You can't do:

void *foo;
// ...
foo += 2.

src/outpacket.c

@@ -23,7 +23,7 @@ static size_t outpacket_counter;
 
 void end_opt6(int container)
 {
-   void *p = daemon->outpacket.iov_base + container + 2;
+   uint8_t *p = (uint8_t *)daemon->outpacket.iov_base + container + 2;
    u16 len = outpacket_counter - container - 4 ;
    
    PUTSHORT(len, p);
@@ -50,11 +50,11 @@ int save_counter(int newval)
 
 void *expand(size_t headroom)
 {
-  void *ret;
+  uint8_t *ret;
 
   if (expand_buf(&daemon->outpacket, outpacket_counter + headroom))
     {
-      ret = daemon->outpacket.iov_base + outpacket_counter;
+      ret = (uint8_t *)daemon->outpacket.iov_base + outpacket_counter;
       outpacket_counter += headroom;
       return ret;
     }
@@ -65,7 +65,7 @@ void *expand(size_t headroom)
 int new_opt6(int opt)
 {
   int ret = outpacket_counter;
-  void *p;
+  unsigned char *p;
 
   if ((p = expand(4)))
     {
@@ -88,7 +88,7 @@ void *put_opt6(void *data, size_t len)
   
 void put_opt6_long(unsigned int val)
 {
-  void *p;
+  unsigned char *p;
   
   if ((p = expand(4)))  
     PUTLONG(val, p);
@@ -96,7 +96,7 @@ void put_opt6_long(unsigned int val)
 
 void put_opt6_short(unsigned int val)
 {
-  void *p;
+  uint8_t *p;
 
   if ((p = expand(2)))
     PUTSHORT(val, p);