configure: Support gcc 12

Fix the following classes of errors reported by gcc 12:
* ${variable} may be used uninitialized.
* ${variable} is set but not used.
* argument 2 is null but the corresponding size argument 3 value is 1 [-Werror=nonnull]

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

diff --git a/configure b/configure
index 8182322b21b3d19426ba226636d9fdc42680cb19..110b4f30c7502eb7e5221fd300a409d49313e639 100755 (executable)
--- a/configure
+++ b/configure
@@ -1128,7 +1128,8 @@ cat > $TMPC << EOF
 #include <sched.h>
 int main(int argc, char **argv)
 {
-  cpu_set_t mask;
+  cpu_set_t mask = { };
+
   return sched_setaffinity(0, sizeof(mask), &mask);
 }
 EOF
@@ -1139,7 +1140,8 @@ else
 #include <sched.h>
 int main(int argc, char **argv)
 {
-  cpu_set_t mask;
+  cpu_set_t mask = { };
+
   return sched_setaffinity(0, &mask);
 }
 EOF
@@ -1621,7 +1623,8 @@ cat > $TMPC << EOF
 #include <sched.h>
 int main(int argc, char **argv)
 {
-  struct sched_param p;
+  struct sched_param p = { };
+
   return sched_setscheduler(0, SCHED_IDLE, &p);
 }
 EOF
@@ -1743,7 +1746,9 @@ cat > $TMPC << EOF
 #include <sys/uio.h>
 int main(int argc, char **argv)
 {
-  return pwritev(0, NULL, 1, 0) + preadv(0, NULL, 1, 0);
+  struct iovec iov[1] = { };
+
+  return pwritev(0, iov, 1, 0) + preadv(0, iov, 1, 0);
 }
 EOF
 if compile_prog "" "" "pwritev"; then
@@ -1761,7 +1766,9 @@ cat > $TMPC << EOF
 #include <sys/uio.h>
 int main(int argc, char **argv)
 {
-  return pwritev2(0, NULL, 1, 0, 0) + preadv2(0, NULL, 1, 0, 0);
+  struct iovec iov[1] = { };
+
+  return pwritev2(0, iov, 1, 0, 0) + preadv2(0, iov, 1, 0, 0);
 }
 EOF
 if compile_prog "" "" "pwritev2"; then
@@ -1787,14 +1794,14 @@ cat > $TMPC << EOF
 #include <stdio.h>
 int main(int argc, char **argv)
 {
-  struct addrinfo hints;
-  struct in6_addr addr;
+  struct addrinfo hints = { };
+  struct in6_addr addr = in6addr_any;
   int ret;
 
   ret = getaddrinfo(NULL, NULL, &hints, NULL);
   freeaddrinfo(NULL);
-  printf("%s\n", gai_strerror(ret));
-  addr = in6addr_any;
+  printf("%s %d\n", gai_strerror(ret), addr.s6_addr[0]);
+
   return 0;
 }
 EOF
@@ -2155,9 +2162,7 @@ cat > $TMPC << EOF
 #include <stdlib.h>
 int main(int argc, char **argv)
 {
-  int rc;
-  rc = pmem_is_pmem(NULL, 0);
-  return 0;
+  return pmem_is_pmem(NULL, 0);
 }
 EOF
 if compile_prog "" "-lpmem" "libpmem"; then
@@ -2176,7 +2181,7 @@ if test "$libpmem" = "yes"; then
 #include <stdlib.h>
 int main(int argc, char **argv)
 {
-  pmem_memcpy(NULL, NULL, NULL, NULL);
+  pmem_memcpy(NULL, NULL, 0, 0);
   return 0;
 }
 EOF
@@ -2392,7 +2397,7 @@ int main(int argc, char **argv)
   FILE *mtab = setmntent(NULL, "r");
   struct mntent *mnt = getmntent(mtab);
   endmntent(mtab);
-  return 0;
+  return mnt != NULL;
 }
 EOF
 if compile_prog "" "" "getmntent"; then