rebuilding libc fails

[mojo]

After updating from 9.0 to 9.1 I ran into the very common issue that gettext compilation fails with locale_t being undeclared. The problems I encounter are very well described in that blogpost:
http://rax.org/blog/FreeBSD/gettext.html

So I have rebuilt libiconv, and as gettext fails, I'm trying to rebuildworld as mentioned, which stops at:

/usr/src/lib/libc/gen/glob.c: In function 'match':
/usr/src/lib/libc/gen/glob.c:818: warning: implicit declaration of function '__get_locale'
/usr/src/lib/libc/gen/glob.c:818: error: invalid type argument of '->'
/usr/src/lib/libc/gen/glob.c:818: error: 'XLC_COLLATE' undeclared (first use in this function)
/usr/src/lib/libc/gen/glob.c:818: error: (Each undeclared identifier is reported only once
/usr/src/lib/libc/gen/glob.c:818: error: for each function it appears in.)
/usr/src/lib/libc/gen/glob.c:843: error: dereferencing pointer to incomplete type
/usr/src/lib/libc/gen/glob.c:845: warning: passing argument 1 of '__collate_range_cmp' makes integer from pointer without a cast
/usr/src/lib/libc/gen/glob.c:845: error: too many arguments to function '__collate_range_cmp'
/usr/src/lib/libc/gen/glob.c:846: warning: passing argument 1 of '__collate_range_cmp' makes integer from pointer without a cast
/usr/src/lib/libc/gen/glob.c:846: error: too many arguments to function '__collate_range_cmp'

locale:

LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_COLLATE=C
LC_TIME="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_ALL=

 

[kpa]

I don't remember seeing that many posts on this forums about problems with locale_t being undefined, on what are you basing your claim that it's a very common issue?

Show your /etc/make.conf, /etc/src.conf and describe exactly how you are building world.

 

[mojo]

Both files are nonexistant and world is rebuilt using make buildworld in /usr/src.

Although it's true that more posts are referring to the missing libintl.so.9 after removing gettext, that is not the problem here and as following instructions in UPGRADING doesn't help, I'm curious on how the locale_t issue, as well as my aforementioned one can be solved.