* math/math.h: Move M_* constants before __math.h include.
[__NO_MATH_INLINES || __OPTIMIZE__]: Include __math.h only #if this.
* misc/efgcvt_r.c (ecvt_r): Declare floor, log10, fabs as weak extern.
If log10 is not defined (i.e. no -lm), use stupid loop instead.
* Makerules (lib%.so: lib%_pic.a): Pass -soname switch giving the
library's name including $(libprefix) and major version number.
* locale/locale-ctype.c (allocate_arrays): Use xmalloc and bzero
in place of xcalloc.
* Makeconfig (prefix, exec_prefix, libprefix): Instead of
`ifndef', use the $(origin) function to only set these if they are
undefined, and not if they are defined to empty.
* gnu-versions.h: New file.
* features.h (__GNU_LIBRARY__): Increase value to 5.
