float128: Add conversion from float128 to mpn

Reuse the code for __mpn_extract_long_double to implement
__mpn_extract_float128.

	* include/gmp.h: Include bits/floatn.h
	(__mpn_extract_float128): Declare when __HAVE_DISTINCT_FLOAT128 is 1.
	* stdlib/gmp-impl.h: Also check if alloca is not defined before
	including stack-alloc.h.  It could have been defined by other header
	which not necessarily defines HAVE_ALLOCA.
	* sysdeps/ieee754/float128/Makefile: New file.
	* sysdeps/ieee754/float128/float1282mpn.c: New file.
	* sysdeps/ieee754/float128/float128_private.h: Include gmp.h before
	redefining __mpn_extract_long_double to __mpn_extract_float128, then
	redefine __mpn_extract_long_double to __mpn_extract_float128.
	* sysdeps/ieee754/ldbl-128/ldbl2mpn.c: Replace long double with
	_Float128 to allow float128_private.h overrides.

1 files changed, 2 insertions, 1 deletions

diff --git a/sysdeps/ieee754/ldbl-128/ldbl2mpn.c b/sysdeps/ieee754/ldbl-128/ldbl2mpn.c
index 71a6f043bd..1c79a5dbe5 100644
--- a/sysdeps/ieee754/ldbl-128/ldbl2mpn.c
+++ b/sysdeps/ieee754/ldbl-128/ldbl2mpn.c
@@ -21,6 +21,7 @@
 #include <ieee754.h>
 #include <float.h>
 #include <math.h>
+#include <math_private.h>
 #include <stdlib.h>
 
 /* Convert a `long double' in IEEE854 quad-precision format to a
@@ -31,7 +32,7 @@
 mp_size_t
 __mpn_extract_long_double (mp_ptr res_ptr, mp_size_t size,
 			   int *expt, int *is_neg,
-			   long double value)
+			   _Float128 value)
 {
   union ieee854_long_double u;
   u.d = value;