Failure to compile world

Hi people!
I'm writing here because I'm having issues with compiling world from a

> Symphony# uname -a
> FreeBSD Symphony 9.0-PRERELEASE FreeBSD 9.0-PRERELEASE #2: Fri Dec 16 
> 18:52:44 ART 2011 vertex_at_Symphony:/usr/obj/usr/src/sys/GENERIC i386

Machine with latest source from that date.
I'm using this git mirror (Sorry guys, if I don't tolerate SVN, the less 
I'll tolerate CVS) → https://github.com/freebsd/freebsd-head (I've 
pulled and got this as last commit → 
https://github.com/freebsd/freebsd-head/commit/f700576aa6240ea7133ce4812aec810266bcbfe7 
)

With this /etc/make.conf (I have to clean it up btw)

> Symphony# cat /etc/make.conf
> #################
> # Make.conf
>
> WITHOUT_NOUVEAU=
> # added by use.perl 2011-11-10 19:36:38
> PERL_VERSION=5.12.4
>
> ##############
> # Clang for kernel+world
>
> .if ${.CURDIR:M/usr/src/*} || ${.CURDIR:M/usr/obj/*} || 
> ${.CURDIR:M/sys/*}
> .if !defined(CC) || ${CC} == "cc"
> CC=clang
> .endif
> .if !defined(CXX) || ${CXX} == "c++"
> CXX=clang++
> .endif
> .if !defined(CPP) || ${CPP} == "cpp"
> CPP=clang-cpp
> .endif
>
> # Don't die on warnings
> NO_WERROR=
> WERROR=
> # Don't forget this when using Jails!
> NO_FSCHG=
>
>
> .if defined(WITH_FLAGS)
> WITH_LIBCPLUSPLUS=YES
> .endif
>
>
> .endif
>

And /usr/obj was properly rm -rf'ed
The problem comes with undefined stuff when I'm compiling libc :

>
> clang -fpic -DPIC -O2 -pipe -I/usr/src/lib/libc/include 
> -I/usr/src/lib/libc/../../include -I/usr/src/lib/libc/i386 -DNLS 
> -D__DBINTERFACE_PRIVATE -I/usr/src/lib/libc/../../contrib/gdtoa 
> -DINET6 -I/usr/obj/usr/src/lib/libc -I/usr/src/lib/libc/resolv 
> -D_ACL_PRIVATE -DPOSIX_MISTAKE 
> -I/usr/src/lib/libc/../../contrib/tzcode/stdtime 
> -I/usr/src/lib/libc/stdtime -I/usr/src/lib/libc/locale -DBROKEN_DES 
> -DPORTMAP -DDES_BUILTIN -I/usr/src/lib/libc/rpc -DYP -DNS_CACHING 
> -DSYMBOL_VERSIONING -std=gnu99 -fstack-protector -Wsystem-headers 
> -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign 
> -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality 
> -Wno-unused-function -Wno-conversion -Wno-switch-enum -Wno-empty-body 
> -c _fcntl.S -o _fcntl.So
> clang -O2 -pipe -I/usr/src/lib/libc/include 
> -I/usr/src/lib/libc/../../include -I/usr/src/lib/libc/i386 -DNLS 
> -D__DBINTERFACE_PRIVATE -I/usr/src/lib/libc/../../contrib/gdtoa 
> -DINET6 -I/usr/obj/usr/src/lib/libc -I/usr/src/lib/libc/resolv 
> -D_ACL_PRIVATE -DPOSIX_MISTAKE 
> -I/usr/src/lib/libc/../../contrib/tzcode/stdtime 
> -I/usr/src/lib/libc/stdtime -I/usr/src/lib/libc/locale -DBROKEN_DES 
> -DPORTMAP -DDES_BUILTIN -I/usr/src/lib/libc/rpc -DYP -DNS_CACHING 
> -DSYMBOL_VERSIONING -std=gnu99 -fstack-protector -Wsystem-headers 
> -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign 
> -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality 
> -Wno-unused-function -Wno-conversion -Wno-switch-enum -Wno-empty-body 
> -c _sigwait.S
> clang -fpic -DPIC -O2 -pipe -I/usr/src/lib/libc/include 
> -I/usr/src/lib/libc/../../include -I/usr/src/lib/libc/i386 -DNLS 
> -D__DBINTERFACE_PRIVATE -I/usr/src/lib/libc/../../contrib/gdtoa 
> -DINET6 -I/usr/obj/usr/src/lib/libc -I/usr/src/lib/libc/resolv 
> -D_ACL_PRIVATE -DPOSIX_MISTAKE 
> -I/usr/src/lib/libc/../../contrib/tzcode/stdtime 
> -I/usr/src/lib/libc/stdtime -I/usr/src/lib/libc/locale -DBROKEN_DES 
> -DPORTMAP -DDES_BUILTIN -I/usr/src/lib/libc/rpc -DYP -DNS_CACHING 
> -DSYMBOL_VERSIONING -std=gnu99 -fstack-protector -Wsystem-headers 
> -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign 
> -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality 
> -Wno-unused-function -Wno-conversion -Wno-switch-enum -Wno-empty-body 
> -c _sigwait.S -o _sigwait.So
> clang -O2 -pipe -I/usr/src/lib/libc/include 
> -I/usr/src/lib/libc/../../include -I/usr/src/lib/libc/i386 -DNLS 
> -D__DBINTERFACE_PRIVATE -I/usr/src/lib/libc/../../contrib/gdtoa 
> -DINET6 -I/usr/obj/usr/src/lib/libc -I/usr/src/lib/libc/resolv 
> -D_ACL_PRIVATE -DPOSIX_MISTAKE 
> -I/usr/src/lib/libc/../../contrib/tzcode/stdtime 
> -I/usr/src/lib/libc/stdtime -I/usr/src/lib/libc/locale -DBROKEN_DES 
> -DPORTMAP -DDES_BUILTIN -I/usr/src/lib/libc/rpc -DYP -DNS_CACHING 
> -DSYMBOL_VERSIONING -std=gnu99 -fstack-protector -Wsystem-headers 
> -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign 
> -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality 
> -Wno-unused-function -Wno-conversion -Wno-switch-enum -Wno-empty-body 
> -c /usr/src/lib/libc/db/btree/bt_close.c -o bt_close.o
> In file included from /usr/src/lib/libc/db/btree/bt_close.c:44:
> /usr/src/lib/libc/../../include/stdlib.h:79:1: error: unknown type 
> name '_Noreturn'
> _Noreturn void abort(void);
> ^
> /usr/src/lib/libc/../../include/stdlib.h:79:11: error: expected 
> identifier or '('
> _Noreturn void abort(void);
> ^
> /usr/src/lib/libc/../../include/stdlib.h:89:1: error: unknown type 
> name '_Noreturn'
> _Noreturn void exit(int);
> ^
> /usr/src/lib/libc/../../include/stdlib.h:89:11: error: expected 
> identifier or '('
> _Noreturn void exit(int);
> ^
> /usr/src/lib/libc/../../include/stdlib.h:148:1: error: unknown type 
> name '_Noreturn'
> _Noreturn void _Exit(int);
> ^
> /usr/src/lib/libc/../../include/stdlib.h:148:11: error: expected 
> identifier or '('
> _Noreturn void _Exit(int);
> ^
> 6 errors generated.
> *** Error code 1
> 1 error
> *** Error code 2
> 1 error
> *** Error code 2
> 1 error
> *** Error code 2
> 1 error
> *** Error code 2
> 1 error
> Symphony# 

Sorry for the long mail, if you need any information, just tell me.

Thanks for your time !