### Description

Unable to upgrade Kamailio 5.7 on CentOS7

Error: ``` tls_mod.c: In function ‘fork_child’: tls_mod.c:348:2: error: ‘for’ loop initial declarations are only allowed in C99 mode for(int k = 0; k < 16; k++) { ^ tls_mod.c:348:2: note: use option -std=c99 or -std=gnu99 to compile your code make[2]: *** [tls_mod.o] Error 1 make[1]: *** [modules] Error 1 ```

### Additional Information

* **Kamailio Version** - output of `kamailio -v` Current installed version: ``` version: kamailio 5.7.4 (x86_64/linux) 2e6e87 ```