I try to upgrade asterisk from 15.5.1 to 16.6.0 on CentOS 6.10
config
./contrib/scripts/install_prereq install
./configure --libdir=/usr/lib64 --with-jansson-bundled --with-pjproject-bundled NOISY_BUILD=yes
make
gcc -c -Wall -DPJ_AUTOCONF=1 -fPIC -Wno-unused-but-set-variable -Wno-unused-variable -Wno-unused-label -Wno-unused-function -Wno-strict-aliasing -pthread -pipe -g3 -O3 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -DPJ_IS_BIG_ENDIAN=0 -DPJ_IS_LITTLE_ENDIAN=1 -fPIC -Wno-unused-but-set-variable -Wno-unused-variable -Wno-unused-label -Wno-unused-function -Wno-strict-aliasing -pthread -pipe -g3 -O3 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fPIC -Wno-unused-but-set-variable -Wno-unused-variable -Wno-unused-label -Wno-unused-function -Wno-strict-aliasing -I…/include
-o output/pjlib-x86_64-unknown-linux-gnu/ssl_sock_ossl.o
…/src/pj/ssl_sock_ossl.c
In file included from …/src/pj/ssl_sock_ossl.c:40:
…/src/pj/ssl_sock_imp_common.h:142: error: redefinition of typedef ‘pj_ssl_sock_t’
…/include/pj/ssl_sock.h:53: note: previous declaration of ‘pj_ssl_sock_t’ was here
make[4]: *** [output/pjlib-x86_64-unknown-linux-gnu/ssl_sock_ossl.o] Error 1
make[4]: Leaving directory /home/ippbx/PKG/5.Asterisk/asterisk-16.6.0/third-party/pjproject/source/pjlib/build' make[3]: *** [libpj-x86_64-unknown-linux-gnu.a] Error 2 make[3]: Leaving directory/home/ippbx/PKG/5.Asterisk/asterisk-16.6.0/third-party/pjproject/source/pjlib/build’
make[2]: *** [/home/ippbx/PKG/5.Asterisk/asterisk-16.6.0/third-party/pjproject/source/pjlib/lib/libpj-x86_64-unknown-linux-gnu.a] Error 2
make[2]: Leaving directory /home/ippbx/PKG/5.Asterisk/asterisk-16.6.0/third-party/pjproject' make[1]: *** [pjproject] Error 2 make[1]: Leaving directory/home/ippbx/PKG/5.Asterisk/asterisk-16.6.0/third-party’
make: *** [third-party] Error 2
But Asterisk 15.5.1 is compiled well on CentOS 6.10