combining signbitl.c

[coypu%sdf.org@localhost]

hi,

i386, m68k, sparc64, x86_64 have their own version of signbitl.c
I don't believe this is necessary. It is an exact copy.

80 bit and 128 bit differences are handled under the struct ieee_ext.

ok to make all users use signbitl_ieee754.c?

Index: arch/x86_64/gen/Makefile.inc
===================================================================
RCS file: /cvsroot/src/lib/libc/arch/x86_64/gen/Makefile.inc,v
retrieving revision 1.18
diff -u -r1.18 Makefile.inc
--- arch/x86_64/gen/Makefile.inc	15 Jul 2015 14:27:49 -0000	1.18
+++ arch/x86_64/gen/Makefile.inc	13 Apr 2019 22:04:37 -0000
@@ -21,10 +21,10 @@
 SRCS+=	isfinitef_ieee754.c isfinited_ieee754.c
 SRCS+=	isinff_ieee754.c isinfd_ieee754.c
 SRCS+=	isnanf_ieee754.c isnand_ieee754.c
-SRCS+=	signbitf_ieee754.c signbitd_ieee754.c
+SRCS+=	signbitf_ieee754.c signbitd_ieee754.c signbitl_ieee754.c
 
 SRCS+=	nanf.c infinityl.c
-SRCS+=	fpclassifyl.c isfinitel.c isinfl.c isnanl.c signbitl.c
+SRCS+=	fpclassifyl.c isfinitel.c isinfl.c isnanl.c
 
 LSRCS.x86_64.gen=\
 	Lint__setjmp.c Lint_alloca.c Lint_bswap16.c Lint_bswap32.c \

Index: gen/signbitl_ieee754.c
===================================================================
RCS file: /cvsroot/src/lib/libc/gen/signbitl_ieee754.c,v
retrieving revision 1.1
diff -u -r1.1 signbitl_ieee754.c
--- gen/signbitl_ieee754.c	17 Jan 2011 23:53:03 -0000	1.1
+++ gen/signbitl_ieee754.c	13 Apr 2019 22:05:13 -0000
@@ -41,7 +41,10 @@
 
 /*
  * 7.12.3.6 signbit - determine whether the sign of an argument is negative
- *          IEEE 754 compatible 128-bit extended-precision version
+ *          IEEE 754 compatible extended-precision version
+ *
+ *          Differences between 128-bit and 80-bit long double are handled
+ *          by a difference in struct ieee_ext.
  */
 int
 __signbitl(long double x)