[PATCH v2 26/28] math: Handle fabsf128 !__USE_EXTERN_INLINES

[Adhemerval Zanella]

clang on x86_64 fails to build s_fabsf128.c with:

../sysdeps/ieee754/float128/../ldbl-128/s_fabsl.c:32:1: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
   32 | libm_alias_ldouble (__fabs, fabs)
      | ^
../sysdeps/generic/libm-alias-ldouble.h:63:38: note: expanded from macro 'libm_alias_ldouble'
   63 | #define libm_alias_ldouble(from, to) libm_alias_ldouble_r (from, to, )
      |                                      ^
../sysdeps/ieee754/float128/float128_private.h:133:43: note: expanded from macro 'libm_alias_ldouble_r'
  133 | #define libm_alias_ldouble_r(from, to, r) libm_alias_float128_r (from, to, r)
      |                                           ^
../sysdeps/ieee754/float128/s_fabsf128.c:5:3: note: expanded from macro 'libm_alias_float128_r'
    5 |   static_weak_alias (from ## f128 ## r, to ## f128 ## r);       \
      |   ^
./../include/libc-symbols.h:166:46: note: expanded from macro 'static_weak_alias'
  166 | #  define static_weak_alias(name, aliasname) weak_alias (name, aliasname)
      |                                              ^
./../include/libc-symbols.h:154:38: note: expanded from macro 'weak_alias'
  154 | # define weak_alias(name, aliasname) _weak_alias (name, aliasname)
      |                                      ^
./../include/libc-symbols.h:156:52: note: expanded from macro '_weak_alias'
  156 |   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))) \
      |                                                    ^
../include/math.h:134:1: note: previous definition is here
  134 | fabsf128 (_Float128 x)

If compiler does not support __USE_EXTERN_INLINES we need to route
fabsf128 call to an internal symbol.
---
 include/math.h                        | 11 ++++++++---
 sysdeps/ieee754/float128/s_fabsf128.c |  3 +++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/include/math.h b/include/math.h
index 0fac2fda84..a6d211af75 100644
--- a/include/math.h
+++ b/include/math.h
@@ -114,9 +114,11 @@ __issignalingf (float x)
 
 # if __HAVE_DISTINCT_FLOAT128
 
+#  ifdef __USE_EXTERN_INLINES
+
 /* __builtin_isinf_sign is broken in GCC < 7 for float128.  */
-#  if ! __GNUC_PREREQ (7, 0)
-#   include <ieee754_float128.h>
+#   if ! __GNUC_PREREQ (7, 0)
+#    include <ieee754_float128.h>
 extern inline int
 __isinff128 (_Float128 x)
 {
@@ -126,13 +128,16 @@ __isinff128 (_Float128 x)
   lx |= -lx;
   return ~(lx >> 63) & (hx >> 62);
 }
-#  endif
+#   endif
 
 extern inline _Float128
 fabsf128 (_Float128 x)
 {
   return __builtin_fabsf128 (x);
 }
+#  else
+libm_hidden_proto (fabsf128)
+#  endif
 # endif
 
 
diff --git a/sysdeps/ieee754/float128/s_fabsf128.c b/sysdeps/ieee754/float128/s_fabsf128.c
index 2c1f277653..9d64f15040 100644
--- a/sysdeps/ieee754/float128/s_fabsf128.c
+++ b/sysdeps/ieee754/float128/s_fabsf128.c
@@ -6,3 +6,6 @@
   libm_alias_float128_other_r (from, to, r)
 #endif
 #include "../ldbl-128/s_fabsl.c"
+#ifndef __USE_EXTERN_INLINES
+libm_hidden_def (fabsf128)
+#endif
-- 
2.43.0