build: untangle CURLDEBUG and DEBUGBUILD macros

`CURLDEBUG` is meant to enable memory tracking, but in a bunch of cases,
it was protecting debug features that were supposed to be guarded with
`DEBUGBUILD`.

Replace these uses with `DEBUGBUILD`.

This leaves `CURLDEBUG` uses solely for its intended  purpose: to enable
the memory tracking debug feature.

Also:
- autotools: rely on `DEBUGBUILD` to enable `checksrc`.
  Instead of `CURLDEBUG`, which worked in most cases because debug
  builds enable `CURLDEBUG` by default, but it's not accurate.
- include `lib/easyif.h` instead of keeping a copy of a declaration.
- add CI test jobs for the build issues discovered.

Ref: https://github.com/curl/curl/pull/13694#issuecomment-2120311894
Closes #13718

lib/Makefile.am

@@ -126,7 +126,7 @@ checksrc:
 	-W$(srcdir)/curl_config.h $(srcdir)/*.[ch] $(srcdir)/vauth/*.[ch]   \
 	$(srcdir)/vtls/*.[ch] $(srcdir)/vquic/*.[ch] $(srcdir)/vssh/*.[ch])
 
-if CURLDEBUG
+if DEBUGBUILD
 # for debug builds, we scan the sources on all regular make invokes
 all-local: checksrc
 endif

lib/cfilters.c

@@ -718,7 +718,7 @@ CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
   DEBUGASSERT(data);
   DEBUGASSERT(data->conn);
   conn = data->conn;
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   {
     /* Allow debug builds to override this logic to force short sends
     */

lib/conncache.h

@@ -50,7 +50,7 @@ struct conncache {
 #define BUNDLE_UNKNOWN     0  /* initial value */
 #define BUNDLE_MULTIPLEX   2
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 /* the debug versions of these macros make extra certain that the lock is
    never doubly locked or unlocked */
 #define CONNCACHE_LOCK(x)                                               \

lib/doh.c

@@ -191,7 +191,7 @@ doh_write_cb(const void *contents, size_t size, size_t nmemb, void *userp)
   return realsize;
 }
 
-#if defined(USE_HTTPSRR) && defined(CURLDEBUG)
+#if defined(USE_HTTPSRR) && defined(DEBUGBUILD)
 static void local_print_buf(struct Curl_easy *data,
                             const char *prefix,
                             unsigned char *buf, size_t len)
@@ -285,7 +285,7 @@ static CURLcode dohprobe(struct Curl_easy *data,
     ERROR_CHECK_SETOPT(CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS);
     ERROR_CHECK_SETOPT(CURLOPT_PIPEWAIT, 1L);
 #endif
-#ifndef CURLDEBUG
+#ifndef DEBUGBUILD
     /* enforce HTTPS if not debug */
     ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
 #else
@@ -870,7 +870,7 @@ static void showdoh(struct Curl_easy *data,
   }
 #ifdef USE_HTTPSRR
   for(i = 0; i < d->numhttps_rrs; i++) {
-# ifdef CURLDEBUG
+# ifdef DEBUGBUILD
     local_print_buf(data, "DoH HTTPS",
                     d->https_rrs[i].val, d->https_rrs[i].len);
 # else
@@ -1143,7 +1143,7 @@ err:
   return CURLE_BAD_CONTENT_ENCODING;
 }
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 static CURLcode test_alpn_escapes(void)
 {
   /* we'll use an example from draft-ietf-dnsop-svcb, figure 10 */
@@ -1176,7 +1176,7 @@ static CURLcode Curl_doh_decode_httpsrr(unsigned char *rrval, size_t len,
   struct Curl_https_rrinfo *lhrr = NULL;
   char *dnsname = NULL;
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   /* a few tests of escaping, shouldn't be here but ok for now */
   if(test_alpn_escapes() != CURLE_OK)
     return CURLE_OUT_OF_MEMORY;
@@ -1244,7 +1244,7 @@ err:
   return CURLE_OUT_OF_MEMORY;
 }
 
-# ifdef CURLDEBUG
+# ifdef DEBUGBUILD
 static void local_print_httpsrr(struct Curl_easy *data,
                                 struct Curl_https_rrinfo *hrr)
 {
@@ -1382,7 +1382,7 @@ CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
         return result;
       }
       infof(data, "Some HTTPS RR to process");
-# ifdef CURLDEBUG
+# ifdef DEBUGBUILD
       local_print_httpsrr(data, hrr);
 # endif
       (*dnsp)->hinfo = hrr;

lib/easy.c

@@ -374,7 +374,7 @@ struct Curl_easy *curl_easy_init(void)
   return data;
 }
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 
 struct socketmonitor {
   struct socketmonitor *next; /* the next node in the list or NULL */
@@ -655,7 +655,7 @@ static CURLcode easy_events(struct Curl_multi *multi)
 
   return wait_or_timeout(multi, &evs);
 }
-#else /* CURLDEBUG */
+#else /* DEBUGBUILD */
 /* when not built with debug, this function doesn't exist */
 #define easy_events(x) CURLE_NOT_BUILT_IN
 #endif
@@ -788,7 +788,7 @@ CURLcode curl_easy_perform(struct Curl_easy *data)
   return easy_perform(data, FALSE);
 }
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 /*
  * curl_easy_perform_ev() is the external interface that performs a blocking
  * transfer using the event-based API internally.

lib/easyif.h

@@ -34,7 +34,7 @@ CURLcode Curl_senddata(struct Curl_easy *data, const void *buffer,
 CURLcode Curl_connect_only_attach(struct Curl_easy *data);
 #endif
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 CURL_EXTERN CURLcode curl_easy_perform_ev(struct Curl_easy *easy);
 #endif
 

lib/http.c

@@ -2849,7 +2849,7 @@ CURLcode Curl_http_header(struct Curl_easy *data,
 #ifndef CURL_DISABLE_ALTSVC
     v = (data->asi &&
          ((data->conn->handler->flags & PROTOPT_SSL) ||
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
           /* allow debug builds to circumvent the HTTPS restriction */
           getenv("CURL_ALTSVC_HTTP")
 #else
@@ -3116,7 +3116,7 @@ CURLcode Curl_http_header(struct Curl_easy *data,
     /* If enabled, the header is incoming and this is over HTTPS */
     v = (data->hsts &&
          ((conn->handler->flags & PROTOPT_SSL) ||
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
            /* allow debug builds to circumvent the HTTPS restriction */
            getenv("CURL_HSTS_HTTP")
 #else

lib/mqtt.c

@@ -585,7 +585,7 @@ static size_t mqtt_decode_len(unsigned char *buf,
   return len;
 }
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
 static const char *statenames[]={
   "MQTT_FIRST",
   "MQTT_REMAINING_LENGTH",
@@ -606,7 +606,7 @@ static void mqstate(struct Curl_easy *data,
 {
   struct connectdata *conn = data->conn;
   struct mqtt_conn *mqtt = &conn->proto.mqtt;
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   infof(data, "%s (from %s) (next is %s)",
         statenames[state],
         statenames[mqtt->state],

lib/rand.c

@@ -105,7 +105,7 @@ static CURLcode randit(struct Curl_easy *data, unsigned int *rnd)
   static unsigned int randseed;
   static bool seeded = FALSE;
 
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   char *force_entropy = getenv("CURL_ENTROPY");
   if(force_entropy) {
     if(!seeded) {

lib/request.c

@@ -187,7 +187,7 @@ static CURLcode xfer_send(struct Curl_easy *data,
   CURLcode result = CURLE_OK;
 
   *pnwritten = 0;
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   {
     /* Allow debug builds to override this logic to force short initial
        sends

lib/url.c

@@ -3028,7 +3028,7 @@ static CURLcode parse_connect_to_slist(struct Curl_easy *data,
 #ifndef CURL_DISABLE_ALTSVC
   if(data->asi && !host && (port == -1) &&
      ((conn->handler->protocol == CURLPROTO_HTTPS) ||
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
       /* allow debug builds to circumvent the HTTPS restriction */
       getenv("CURL_ALTSVC_HTTP")
 #else

lib/urldata.h

@@ -1375,7 +1375,7 @@ struct UrlState {
   unsigned char select_bits; /* != 0 -> bitmask of socket events for this
                                  transfer overriding anything the socket may
                                  report */
-#ifdef CURLDEBUG
+#ifdef DEBUGBUILD
   BIT(conncache_lock);
 #endif
   /* when curl_easy_perform() is called, the multi handle is "owned" by