It’s been a while, but I had to recompile a PHP from source and ran into this problem during the ./configure stage.
$ ./configure ... checking for IMAP Kerberos support... no checking for IMAP SSL support... yes checking for utf8_mime2text signature... new checking for U8T_DECOMPOSE... configure: error: utf8_mime2text() has new signature, but U8T_CANONICAL is missing. This should not happen. Check config.log for additional information.
To resolve that utf8_mime2text() has new signature, but U8T_CANONICAL is missing error, on CentOS you can install the libc-client-devel package.
$ yum install libc-client-devel
After that, your ./configure should go through.