Now `json-c` devel files are found properly. On current master can fix this build ``` [ 63%] Building C object src/modules/ims_usrloc_scscf/CMakeFiles/ims_usrloc_scscf.dir/ul_callback.c.o cd /root/rpmbuild/BUILD/kamailio-6.1.0-dev0/redhat-linux-build/src/modules/ims_usrloc_scscf && /usr/bin/gcc -DADAPTIVE_WAIT -DADAPTIVE_WAIT_LOOPS=1024 -DARCH="x86_64" -DCC_GCC_LIKE_ASM -DCFG_DIR="/etc/kamailio/" -DCOMPILER=""gcc 11.5.0"" -DDBG_SR_MEMORY -DDISABLE_NAGLE -DDNS_IP_HACK -DFAST_LOCK -DFMSTATS -DF_MALLOC -DHAVE_ALLOCA_H -DHAVE_EPOLL -DHAVE_GETHOSTBYNAME2 -DHAVE_IP_MREQN -DHAVE_MSGHDR_MSG_CONTROL -DHAVE_MSG_NOSIGNAL -DHAVE_RESOLV_RES -DHAVE_SCHED_SETSCHEDULER -DHAVE_SCHED_YIELD -DHAVE_SELECT -DHAVE_SIGIO_RT -DHAVE_TIMEGM -DHAVE_UNION_SEMUN -DKMSTATS -DKSR_PTHREAD_MUTEX_SHARED -DMALLOC_STATS -DMOD_NAME="ims_usrloc_scscf" -DMOD_NAMEID=ims_usrloc_scscf -DNAME="kamailio" -DOS=Linux -DOS_QUOTED="Linux" -DPKG_MALLOC -DQ_MALLOC -DRAW_SOCKS -DRUN_DIR="/run/kamailio" -DSHARE_DIR="/usr/share/kamailio/" -DSHM_MMAP -DSIGINFO64_WORKAROUND -DSTATISTICS -DTLSF_MALLOC -DTLS_HOOKS -DUSE_DNS_CACHE -DUSE_DNS_FAILOVER -DUSE_DST_BLOCKLIST -DUSE_MCAST -DUSE_NAPTR -DUSE_RAW_SOCKS -DUSE_SCTP -DUSE_TCP -DUSE_TLS -DVERSION="6.1.0-dev0" -DVERSIONVAL=6001000 -D__CPU_x86_64 -D__OS_linux -Dims_usrloc_scscf_EXPORTS -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -march=x86-64-v2 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -DNDEBUG -std=gnu11 -fPIC -ffile-prefix-map=/root/rpmbuild/BUILD/kamailio-6.1.0-dev0/src/modules/ims_usrloc_scscf/= -fPIC -Wall -funroll-loops -Wcast-align -Werror=implicit-function-declaration -Werror=implicit-int -m64 -minline-all-stringops -falign-loops -ftree-vectorize -fno-strict-overflow -mtune=generic -MD -MT src/modules/ims_usrloc_scscf/CMakeFiles/ims_usrloc_scscf.dir/ul_callback.c.o -MF CMakeFiles/ims_usrloc_scscf.dir/ul_callback.c.o.d -o CMakeFiles/ims_usrloc_scscf.dir/ul_callback.c.o -c /root/rpmbuild/BUILD/kamailio-6.1.0-dev0/src/modules/ims_usrloc_scscf/ul_callback.c /root/rpmbuild/BUILD/kamailio-6.1.0-dev0/src/modules/janssonrpcc/janssonrpc_server.c: In function 'jsonrpc_parse_server': /root/rpmbuild/BUILD/kamailio-6.1.0-dev0/src/modules/janssonrpcc/janssonrpc_server.c:194:16: warning: 'conn.s' may be used uninitialized [-Wmaybe-uninitialized] 194 | if(conn.s == NULL) { | ~~~~^~ /root/rpmbuild/BUILD/kamailio-6.1.0-dev0/src/modules/janssonrpcc/janssonrpc_server.c:132:13: note: 'conn' declared here 132 | str conn; | ^~~~ [ 63%] Building C object src/modules/janssonrpcc/CMakeFiles/janssonrpcc.dir/janssonrpc_srv.c.o ``` For me looks this error is present on the old build but I do have an idea how it can be possible.