so there are a few compiler warnings if the source is built with gcc-14, with :

libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -Wdate-time -D_FORTIFY_SOURCE=2 -D_REENTRANT -g -O2 -Werror=implicit-function-declaration -Werror=array-bounds -Werror=clobbered -Werror=volatile-register-var -ffile-prefix-map=/builds/debian/libnss-mysql/debian/output/source_dir=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wall -I/usr/include/mariadb -I/usr/include/mariadb/mysql -c nss_config.c  -fPIC -DPIC -o .libs/nss_config.o
nss_config.c: In function '_nss_mysql_load_config_file':
nss_config.c:85:11: warning: '__builtin_strncpy' output may be truncated copying 128 bytes from a string of length 1023 [-Wstringop-truncation]
   85 |           strncpy (key, cur, key_size);
      |           ^

...

libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -Wdate-time -D_FORTIFY_SOURCE=2 -D_REENTRANT -g -O2 -Werror=implicit-function-declaration -Werror=array-bounds -Werror=clobbered -Werror=volatile-register-var -ffile-prefix-map=/builds/debian/libnss-mysql/debian/output/source_dir=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wall -I/usr/include/mariadb -I/usr/include/mariadb/mysql -c mysql.c  -fPIC -DPIC -o .libs/mysql.o
...
mysql.c: In function '_nss_mysql_connect_sql':
mysql.c:220:7: warning: the comparison will always evaluate as 'true' for the address of 'port' will never be NULL [-Waddress]
  220 |   if (server->port)
      |       ^~~~~~
In file included from mysql.c:24:
nss_mysql.h:212:8: note: 'port' declared here
  212 |   char port[MAX_VAL_SIZE];      /* SQL port to connect to */
      |        ^~~~


A copy of the full buildlog is here, along with source and amd64 binary package: mgt1.sv.gnu.org:/home/guthib
alternatively, debian's gitlab-runner ci pipeline log: https://salsa.debian.org/debian/libnss-mysql/-/jobs/6781019