[glibc] support: Invent verbose_printf macro

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=8bf225d5832eda8fefce9361c53cb68a55150b96

commit 8bf225d5832eda8fefce9361c53cb68a55150b96
Author: Mike Crowe <mac@mcrowe.com>
Date:   Wed Jun 19 18:06:14 2019 -0300

    support: Invent verbose_printf macro
    
    Make it easier for tests to emit progress messages only when --verbose is
    specified.
    
    * support/test-driver.h: Add verbose_printf macro.

Diff:
---
 ChangeLog             | 2 ++
 support/test-driver.h | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index de58169..a67ffe7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2019-06-20  Mike Crowe  <mac@mcrowe.com>
 
+	* support/test-driver.h: Add verbose_printf macro.
+
 	* support/xtime.h: Add xclock_now() helper function.
 
 2019-06-20  Dmitry V. Levin  <ldv@altlinux.org>
diff --git a/support/test-driver.h b/support/test-driver.h
index a9710af..55f355f 100644
--- a/support/test-driver.h
+++ b/support/test-driver.h
@@ -69,6 +69,14 @@ extern const char *test_dir;
    tests.  */
 extern unsigned int test_verbose;
 
+/* Output that is only emitted if at least one --verbose argument was
+   specified. */
+#define verbose_printf(...)                      \
+  do {                                           \
+    if (test_verbose > 0)                        \
+      printf (__VA_ARGS__);                      \
+  } while (0);
+
 int support_test_main (int argc, char **argv, const struct test_config *);
 
 __END_DECLS