Use libm_alias_double for dbl-64 modf.

This patch makes dbl-64 modf use libm_alias_double.  Both the dbl-64
and dbl-64/wordsize-64 versions are changed, and the ldbl-opt version
is changed to define the libc compat symbol only.  Because of
multiarch wrappers, the changed implementations are made not to define
aliases at all if __modf is defined as a macro, as with other
functions, so avoiding duplicate compat symbols while allowing those
wrappers to be simplified.

Tested for x86_64, and verified with build-many-glibcs.py that
installed stripped shared libraries are unchanged by the patch.

	* sysdeps/ieee754/dbl-64/s_modf.c: Include <libm-alias-double.h>.
	(modf): Define using libm_alias_double, only if [!__modf].
	* sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c: Include
	<libm-alias-double.h>.
	(modf): Define using libm_alias_double, only if [!__modf].
	* sysdeps/ieee754/ldbl-opt/s_modf.c (modfl): Only define libc
	compat symbol here.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_modf-ppc32.c
	(weak_alias): Do not undefine and redefine.
	(strong_alias): Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf-ppc64.c
	(weak_alias): Likewise.
	(strong_alias): Likewise.

ChangeLog

@@ -1,5 +1,19 @@
 2017-10-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/ieee754/dbl-64/s_modf.c: Include <libm-alias-double.h>.
+	(modf): Define using libm_alias_double, only if [!__modf].
+	* sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c: Include
+	<libm-alias-double.h>.
+	(modf): Define using libm_alias_double, only if [!__modf].
+	* sysdeps/ieee754/ldbl-opt/s_modf.c (modfl): Only define libc
+	compat symbol here.
+	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_modf-ppc32.c
+	(weak_alias): Do not undefine and redefine.
+	(strong_alias): Likewise.
+	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf-ppc64.c
+	(weak_alias): Likewise.
+	(strong_alias): Likewise.
+
 	* sysdeps/ieee754/dbl-64/s_logb.c: Include <libm-alias-double.h>.
 	(logb): Define using libm_alias_double, only if [!__logb].
 	* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c: Include

sysdeps/ieee754/dbl-64/s_modf.c

@@ -21,6 +21,7 @@
 
 #include <math.h>
 #include <math_private.h>
+#include <libm-alias-double.h>
 
 static const double one = 1.0;
 
@@ -79,8 +80,6 @@ __modf (double x, double *iptr)
 	}
     }
 }
-weak_alias (__modf, modf)
-#ifdef NO_LONG_DOUBLE
-strong_alias (__modf, __modfl)
-weak_alias (__modf, modfl)
+#ifndef __modf
+libm_alias_double (__modf, modf)
 #endif

sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c

@@ -22,6 +22,7 @@
 
 #include <math.h>
 #include <math_private.h>
+#include <libm-alias-double.h>
 #include <stdint.h>
 
 static const double one = 1.0;
@@ -59,8 +60,6 @@ __modf(double x, double *iptr)
 	    return x;
 	}
 }
-weak_alias (__modf, modf)
-#ifdef NO_LONG_DOUBLE
-strong_alias (__modf, __modfl)
-weak_alias (__modf, modfl)
+#ifndef __modf
+libm_alias_double (__modf, modf)
 #endif

sysdeps/ieee754/ldbl-opt/s_modf.c

@@ -1,9 +1,5 @@
 #include <math_ldbl_opt.h>
 #include <sysdeps/ieee754/dbl-64/s_modf.c>
-#if IS_IN (libm)
-# if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
-compat_symbol (libm, __modf, modfl, GLIBC_2_0);
-# endif
-#elif LONG_DOUBLE_COMPAT(libc, GLIBC_2_0)
+#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
 compat_symbol (libc, __modf, modfl, GLIBC_2_0);
 #endif

sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_modf-ppc32.c

@@ -19,11 +19,6 @@
 #include <math.h>
 #include <math_ldbl_opt.h>
 
-#undef weak_alias
-#define weak_alias(a,b)
-#undef strong_alias
-#define strong_alias(a,b)
-
 #define __modf __modf_ppc32
 
 #include <sysdeps/ieee754/dbl-64/s_modf.c>

sysdeps/powerpc/powerpc64/fpu/multiarch/s_modf-ppc64.c

@@ -19,11 +19,6 @@
 #include <math.h>
 #include <math_ldbl_opt.h>
 
-#undef weak_alias
-#define weak_alias(a,b)
-#undef strong_alias
-#define strong_alias(a,b)
-
 #define __modf __modf_ppc64
 
 #include <sysdeps/ieee754/dbl-64/s_modf.c>