Description:
------------
5.2.1 does not build because it's missing the definition of "U8T_CANONICAL" in the imap extension.
5.2.0 does build without problems.

Reproduce code:
---------------
./configure '--prefix=/usr' '--with-apxs2=/usr/bin/apxs2' '--with-config-file-path=/etc/php5/apache2' '--enable-memory-limit' '--disable-debug' '--with-regex=php' '--disable-rpath' '--disable-static' '--with-pic' '--with-layout=GNU' '--with-pear=/usr/share/php' '--enable-calendar' '--enable-sysvsem' '--enable-sysvshm' '--enable-sysvmsg' '--enable-track-vars' '--enable-trans-sid' '--enable-bcmath' '--with-bz2' '--enable-ctype' '--with-db4' '--with-iconv' '--enable-exif' '--enable-filepro' '--enable-ftp' '--enable-dbase' '--with-gettext' '--enable-mbstring' '--with-pcre-regex' '--enable-shmop' '--enable-sockets' '--enable-wddx' '--enable-tokenizer' '--enable-xml' '--with-expat-dir=/usr' '--enable-bcmath' '--with-bz2' '--enable-ctype' '--with-db4' '--with-iconv' '--enable-exif' '--enable-filepro' '--enable-ftp' '--enable-dbase' '--with-gettext' '--enable-mbstring' '--with-pcre-regex' '--enable-shmop' '--enable-sockets' '--enable-wddx' '--enable-tokenizer' '--with-kerberos=/usr' '--with-openssl=/usr' '--with-zip=/usr' '--enable-dbx' '--with-mime-magic=/usr/share/misc/file/magic.mime' '--with-exec-dir=/usr/lib/php5/libexec' '--without-mm' '--with-mysql' '--without-sybase-ct' --enable-safe-mode --with-gd --with-jpeg --with-png --with-gif --with-ttf --enable-gd-native-ttf --enable-gd-imgstrttf --with-jpeg-dir=/usr/ --with-png-dir=/usr/ --with-freetype-dir=yes --with-imap --with-imap-ssl --with-zlib-dir=/usr

Actual result:
--------------
[...]
checking for IMAP support... yes
checking for IMAP Kerberos support... /usr
checking for IMAP SSL support... yes
checking for utf8_mime2text signature... new
checking for U8T_CANONICAL... no
configure: error: utf8_mime2text() has new signature, but U8T_CANONICAL is missing. This should not happen. Check config.log for additional information.

config.log:
configure:45953: checking for U8T_CANONICAL
configure:45969: gcc -c -I/usr/local/include  -D_REENTRANT conftest.c 1>&5
configure:45960:22: c-client.h: No such file or directory
configure: In function `main':
configure:45964: error: `U8T_CANONICAL' undeclared (first use in this function)
configure:45964: error: (Each undeclared identifier is reported only once
configure:45964: error: for each function it appears in.)
configure: failed program was:
#line 45958 "configure"
#include "confdefs.h"

#include <c-client.h>

int main() {

         int i = U8T_CANONICAL;

; return 0; }