* configure.in: Add some tests for gnu-regex.c's benefit.
See if btowc() function is provided in C library.
* configure, config.in: Regenerated.
* Makefile.in (CLIBS, CDEPS): Add @LIBOBJS@ to build btowc.c
if necessary.
* btowc.c: New file.
* gnu-regex.c: Reorder wchar.h and wctype.h includes for Solaris'
benefit.
Drop namespace preserving defines for now.
