Clang has its own <tgmath.h> and doesn't use <tgmath.h> from glibc.  Pass
"-I." to compiler only if $($(<F)-no-include-dot) are undefined.  Define
it to yes for tgmath tests when testing with Clang.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>

1998-09-06 09:53 -0400  Zack Weinberg  <zack@rabi.phys.columbia.edu>

	* Makeconfig (+gccwarn): Remove -Wno-parentheses.

	* elf/dl-open.c: Quiet -Wparentheses warnings.
	* iconvdata/johab.c: Likewise.
	* iconvdata/uhc.c: Likewise.
	* inet/inet_net.c: Likewise.
	* io/fts.c: Likewise.
	* locale/newlocale.c: Likewise.
	* misc/getttyent.c: Likewise.
	* misc/mntent_r.c: Likewise.
	* misc/ttyslot.c: Likewise.
	* nscd/nscd_conf.c: Likewise.
	* nss/nsswitch.c: Likewise.
	* resolv/gethnamaddr.c: Likewise.
	* resolv/nsap_addr.c: Likewise.
	* resolv/res_debug.c: Likewise.
	* stdio-common/_itoa.c: Likewise.
	* stdlib/strtod.c: Likewise.
	* string/strverscmp.c: Likewise.
	* sunrpc/svc.c: Likewise.
	* sysdeps/libm-ieee754/e_cosh.c: Likewise.
	* sysdeps/libm-ieee754/e_gamma_r.c: Likewise.
	* sysdeps/libm-ieee754/e_sinh.c: Likewise.
	* sysdeps/posix/getaddrinfo.c: Likewise.

	* include/dlfcn.h: Likewise.
	* elf/dlfcn.h: Declare dladdr only for __USE_GNU.
	Define RTLD_DEFAULT.