Merge bitcoin/bitcoin#27401: tracepoints: Disables -Wgnu-zero-variadic-macro-arguments to compile without warnings

5197660 tracepoints: Disables `-Wgnu-zero-variadic-macro-arguments` to compile without warnings (Martin Leitner-Ankerl)

Pull request description:

  Fixes #26916 by disabling the warning `-Wgnu-zero-variadic-macro-arguments` when clang is used as the compiler.

  Also see the comments
  * Proposed changes in the bug  bitcoin/bitcoin#26916 (comment)
  * Proposed changes when moving to a variadic maro: bitcoin/bitcoin#26593 (comment)

ACKs for top commit:
  hebasto:
    ACK 5197660, I've reconsidered my [comment](bitcoin/bitcoin#27401 (comment)) and I think the current localized approach is optimal.
  fanquake:
    ACK 5197660 - checked that this fixes the warnings under Clang.

Tree-SHA512: c3dda3bcbb2540af6283ffff65885a9937bfdaaef3b00dc7d60b9f9740031d5c36ac9cb3d3d8756dbadce4812201a9754f5b8770df0d5e0d5ee690ba8a7135d2

Author: fanquake

src/util/trace.h

@@ -9,19 +9,28 @@
 
 #include <sys/sdt.h>
 
-#define TRACE(context, event) DTRACE_PROBE(context, event)
-#define TRACE1(context, event, a) DTRACE_PROBE1(context, event, a)
-#define TRACE2(context, event, a, b) DTRACE_PROBE2(context, event, a, b)
-#define TRACE3(context, event, a, b, c) DTRACE_PROBE3(context, event, a, b, c)
-#define TRACE4(context, event, a, b, c, d) DTRACE_PROBE4(context, event, a, b, c, d)
-#define TRACE5(context, event, a, b, c, d, e) DTRACE_PROBE5(context, event, a, b, c, d, e)
-#define TRACE6(context, event, a, b, c, d, e, f) DTRACE_PROBE6(context, event, a, b, c, d, e, f)
-#define TRACE7(context, event, a, b, c, d, e, f, g) DTRACE_PROBE7(context, event, a, b, c, d, e, f, g)
-#define TRACE8(context, event, a, b, c, d, e, f, g, h) DTRACE_PROBE8(context, event, a, b, c, d, e, f, g, h)
-#define TRACE9(context, event, a, b, c, d, e, f, g, h, i) DTRACE_PROBE9(context, event, a, b, c, d, e, f, g, h, i)
-#define TRACE10(context, event, a, b, c, d, e, f, g, h, i, j) DTRACE_PROBE10(context, event, a, b, c, d, e, f, g, h, i, j)
-#define TRACE11(context, event, a, b, c, d, e, f, g, h, i, j, k) DTRACE_PROBE11(context, event, a, b, c, d, e, f, g, h, i, j, k)
-#define TRACE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l) DTRACE_PROBE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l)
+// Disabling this warning can be removed once we switch to C++20
+#if defined(__clang__) && __cplusplus < 202002L
+#define BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wgnu-zero-variadic-macro-arguments\"")
+#define BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP _Pragma("clang diagnostic pop")
+#else
+#define BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH
+#define BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#endif
+
+#define TRACE(context, event) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE(context, event) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE1(context, event, a) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE1(context, event, a) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE2(context, event, a, b) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE2(context, event, a, b) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE3(context, event, a, b, c) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE3(context, event, a, b, c) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE4(context, event, a, b, c, d) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE4(context, event, a, b, c, d) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE5(context, event, a, b, c, d, e) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE5(context, event, a, b, c, d, e) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE6(context, event, a, b, c, d, e, f) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE6(context, event, a, b, c, d, e, f) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE7(context, event, a, b, c, d, e, f, g) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE7(context, event, a, b, c, d, e, f, g) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE8(context, event, a, b, c, d, e, f, g, h) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE8(context, event, a, b, c, d, e, f, g, h) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE9(context, event, a, b, c, d, e, f, g, h, i) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE9(context, event, a, b, c, d, e, f, g, h, i) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE10(context, event, a, b, c, d, e, f, g, h, i, j) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE10(context, event, a, b, c, d, e, f, g, h, i, j) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE11(context, event, a, b, c, d, e, f, g, h, i, j, k) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE11(context, event, a, b, c, d, e, f, g, h, i, j, k) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
+#define TRACE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_PUSH DTRACE_PROBE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l) BITCOIN_DISABLE_WARN_ZERO_VARIADIC_POP
 
 #else