diff --git a/glib/gnulib/gl_cv_func_printf_directive_f/meson.build b/glib/gnulib/gl_cv_func_printf_directive_f/meson.build
index afde78bf8..5137e98b1 100644
--- a/glib/gnulib/gl_cv_func_printf_directive_f/meson.build
+++ b/glib/gnulib/gl_cv_func_printf_directive_f/meson.build
@@ -15,7 +15,7 @@ static double zero = 0.0;
 int main ()
 {
   int result = 0;
-  if (sprintf (buf, "%F %d", 1234567.0, 33, 44, 55) < 0
+  if (sprintf (buf, "%F %d", 1234567.0, 33) < 0
       || strcmp (buf, "1234567.000000 33") != 0)
     result |= 1;
   if (sprintf (buf, "%F", 1.0 / zero) < 0
diff --git a/glib/gnulib/gl_cv_func_printf_flag_zero/meson.build b/glib/gnulib/gl_cv_func_printf_flag_zero/meson.build
index 2cb00a8e5..eea5dbb70 100644
--- a/glib/gnulib/gl_cv_func_printf_flag_zero/meson.build
+++ b/glib/gnulib/gl_cv_func_printf_flag_zero/meson.build
@@ -15,7 +15,7 @@ static char buf[100];
 static double zero = 0.0;
 int main ()
 {
-  if (sprintf (buf, "%010f", 1.0 / zero, 33, 44, 55) < 0
+  if (sprintf (buf, "%010f", 1.0 / zero) < 0
       || (strcmp (buf, "       inf") != 0
           && strcmp (buf, "  infinity") != 0))
     return 1;
diff --git a/glib/gnulib/gl_cv_func_printf_long_double/meson.build b/glib/gnulib/gl_cv_func_printf_long_double/meson.build
index 3d0e01934..2659ca39a 100644
--- a/glib/gnulib/gl_cv_func_printf_long_double/meson.build
+++ b/glib/gnulib/gl_cv_func_printf_long_double/meson.build
@@ -15,15 +15,15 @@ int main ()
 {
   int result = 0;
   buf[0] = '\0';
-  if (sprintf (buf, "%Lf %d", 1.75L, 33, 44, 55) < 0
+  if (sprintf (buf, "%Lf %d", 1.75L, 33) < 0
       || strcmp (buf, "1.750000 33") != 0)
     result |= 1;
   buf[0] = '\0';
-  if (sprintf (buf, "%Le %d", 1.75L, 33, 44, 55) < 0
+  if (sprintf (buf, "%Le %d", 1.75L, 33) < 0
       || strcmp (buf, "1.750000e+00 33") != 0)
     result |= 2;
   buf[0] = '\0';
-  if (sprintf (buf, "%Lg %d", 1.75L, 33, 44, 55) < 0
+  if (sprintf (buf, "%Lg %d", 1.75L, 33) < 0
       || strcmp (buf, "1.75 33") != 0)
     result |= 4;
   return result;
diff --git a/meson.build b/meson.build
index 60bc7b573..b291fe333 100644
--- a/meson.build
+++ b/meson.build
@@ -1027,6 +1027,7 @@ static __uint128_t v1 = 100;
 static __uint128_t v2 = 10;
 static __uint128_t u;
 u = v1 / v2;
+(void) u;
 }'''
 if cc.compiles(uint128_t_src, name : '__uint128_t available')
   glib_conf.set('HAVE_UINT128_T', 1)
@@ -1122,7 +1123,7 @@ if cc.compiles('''#include <fcntl.h>
                   #include <sys/types.h>
                   #include <sys/stat.h>
                   void some_func (void) {
-                    open(0, O_DIRECTORY, 0);
+                    open(".", O_DIRECTORY, 0);
                   }''', name : 'open() option O_DIRECTORY')
   glib_conf.set('HAVE_OPEN_O_DIRECTORY', 1)
 endif
@@ -1227,7 +1228,6 @@ int
 doit()
 {
   char buffer[32];
-  va_list args;
   int r;
 
   r = snprintf(buffer, 5, "1234567");
@@ -1314,6 +1314,7 @@ endif
 if cc.links('''#include <langinfo.h>
                int main (int argc, char ** argv) {
                  char *codeset = nl_langinfo (CODESET);
+                 (void) codeset;
                  return 0;
                }''', name : 'nl_langinfo and CODESET')
   glib_conf.set('HAVE_LANGINFO_CODESET', 1)
@@ -1334,6 +1335,7 @@ if cc.links('''#include <langinfo.h>
                  str = nl_langinfo (ABMON_12);
                  str = nl_langinfo (DAY_1);
                  str = nl_langinfo (ABDAY_7);
+                 (void) str;
                  return 0;
                }''', name : 'nl_langinfo (PM_STR)')
   have_langinfo_time = true
@@ -1349,6 +1351,7 @@ if cc.links('''#include <langinfo.h>
                  str = nl_langinfo (ERA_D_FMT);
                  str = nl_langinfo (ERA_T_FMT);
                  str = nl_langinfo (_NL_TIME_ERA_NUM_ENTRIES);
+                 (void) str;
                  return 0;
                }''', name : 'nl_langinfo (ERA)')
   glib_conf.set('HAVE_LANGINFO_ERA', 1)
@@ -1370,6 +1373,7 @@ if cc.links('''#include <langinfo.h>
                  str = nl_langinfo (_NL_CTYPE_OUTDIGIT7_MB);
                  str = nl_langinfo (_NL_CTYPE_OUTDIGIT8_MB);
                  str = nl_langinfo (_NL_CTYPE_OUTDIGIT9_MB);
+                 (void) str;
                  return 0;
                }''', name : 'nl_langinfo (_NL_CTYPE_OUTDIGITn_MB)')
   glib_conf.set('HAVE_LANGINFO_OUTDIGIT', 1)
@@ -1397,6 +1401,7 @@ if cc.links('''#ifndef _GNU_SOURCE
                  str = nl_langinfo (ALTMON_10);
                  str = nl_langinfo (ALTMON_11);
                  str = nl_langinfo (ALTMON_12);
+                 (void) str;
                  return 0;
                }''', name : 'nl_langinfo (ALTMON_n)')
   glib_conf.set('HAVE_LANGINFO_ALTMON', 1)
@@ -1424,6 +1429,7 @@ if cc.links('''#ifndef _GNU_SOURCE
                  str = nl_langinfo (_NL_ABALTMON_10);
                  str = nl_langinfo (_NL_ABALTMON_11);
                  str = nl_langinfo (_NL_ABALTMON_12);
+                 (void) str;
                  return 0;
                }''', name : 'nl_langinfo (_NL_ABALTMON_n)')
   glib_conf.set('HAVE_LANGINFO_ABALTMON', 1)
@@ -1436,6 +1442,7 @@ endif
 if cc.links('''#include <langinfo.h>
                int main (int argc, char ** argv) {
                  char *codeset = nl_langinfo (_NL_TIME_CODESET);
+                 (void) codeset;
                  return 0;
                }''', name : 'nl_langinfo and _NL_TIME_CODESET')
   glib_conf.set('HAVE_LANGINFO_TIME_CODESET', 1)
@@ -1506,6 +1513,7 @@ if cc.compiles('''#include <sys/types.h>
                   #include <inttypes.h>
                   void some_func (void) {
                     uintmax_t i = (uintmax_t) -1;
+                    (void) i;
                   }''', name : 'uintmax_t in inttypes.h')
   glib_conf.set('HAVE_INTTYPES_H_WITH_UINTMAX', 1)
   found_uintmax_t = true
@@ -1518,6 +1526,7 @@ if cc.compiles('''#include <sys/types.h>
                   #include <stdint.h>
                   void some_func (void) {
                     uintmax_t i = (uintmax_t) -1;
+                    (void) i;
                   }''', name : 'uintmax_t in stdint.h')
   glib_conf.set('HAVE_STDINT_H_WITH_UINTMAX', 1)
   found_uintmax_t = true