Fix bits/math-finite.h _MSUF_ expansion namespace (bug 22028).

The current bits/math-finite.h approach to defining functions for
different types, involving math.h defining _MSUF_ and _MSUFTO_ for the
function suffixes involved, is not namespace-clean if one of those
suffixes (f, l, f128) is defined as a macro by the user before math.h
is included; too many levels of macro expansion occur.  Instead, those
suffixes should appear directly in the expansion of the macro using ##
so they don't get expanded even if defined as macros by the user (that
is, math.h should be defining __REDIRFROM_X and __REDIRTO_X directly
to use those suffixes rather than suffixes being passed as an argument
by macro callers).  This patch makes that change.

Tested for x86_64.

	[BZ #22028]
	* math/math.h [__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0]
	(_MSUF_): Remove macro.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0] (_MSUFTO_):
	Likewise.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0]
	(__REDIRFROM_X): New macro.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0] (__REDIRTO_X):
	Likewise.
	* math/bits/math-finite.h (__REDIRFROM_X): Remove macro.
	(__REDIRTO_X): Likewise.
	(__MATH_REDIRCALL): Do not pass _MSUF_ or _MSUFTO_ macro
	arguments.
	(__MATH_REDIRCALL_2): Likewise.
	(__MATH_REDIRCALL_INTERNAL): Likewise.
	(__REDIRFROM (lgamma, , _MSUF_)): Likewise.
	(__REDIRFROM (gamma, , _MSUF_)): Likweise.
	(__REDIRFROM (__gamma, _r_finite, _MSUF_)): Likewise.
	(__REDIRFROM (tgamma, , _MSUF_)): Likewise.
	* math/test-finite-macros.c: New file.
	* math/Makefile (tests): Add test-finite-macros.
	(CFLAGS-test-finite-macros.c): New variable.

1 files changed, 28 insertions, 18 deletions

diff --git a/math/math.h b/math/math.h
index f3eb677a40..7e41b0dd3a 100644
--- a/math/math.h
+++ b/math/math.h
@@ -644,14 +644,16 @@ iszero (__T __val)
 # define _Mdouble_ double
 # define __MATH_DECLARING_DOUBLE 1
 # define __MATH_DECLARING_FLOATN 0
-# define _MSUF_
-# define _MSUFTO_
+# define __REDIRFROM_X(function, reentrant) \
+  function ## reentrant
+# define __REDIRTO_X(function, reentrant) \
+   __ ## function ## reentrant ## _finite
 # include <bits/math-finite.h>
 # undef _Mdouble_
 # undef __MATH_DECLARING_DOUBLE
 # undef __MATH_DECLARING_FLOATN
-# undef _MSUF_
-# undef _MSUFTO_
+# undef __REDIRFROM_X
+# undef __REDIRTO_X
 
 /* When __USE_ISOC99 is defined, include math-finite for float and
    long double, as well.  */
@@ -661,32 +663,37 @@ iszero (__T __val)
 #  define _Mdouble_ float
 #  define __MATH_DECLARING_DOUBLE 0
 #  define __MATH_DECLARING_FLOATN 0
-#  define _MSUF_ f
-#  define _MSUFTO_ f
+#  define __REDIRFROM_X(function, reentrant) \
+  function ## f ## reentrant
+#  define __REDIRTO_X(function, reentrant) \
+   __ ## function ## f ## reentrant ## _finite
 #  include <bits/math-finite.h>
 #  undef _Mdouble_
 #  undef __MATH_DECLARING_DOUBLE
 #  undef __MATH_DECLARING_FLOATN
-#  undef _MSUF_
-#  undef _MSUFTO_
+#  undef __REDIRFROM_X
+#  undef __REDIRTO_X
 
 /* Include bits/math-finite.h for long double.  */
 #  ifdef __MATH_DECLARE_LDOUBLE
 #   define _Mdouble_ long double
 #   define __MATH_DECLARING_DOUBLE 0
 #   define __MATH_DECLARING_FLOATN 0
-#   define _MSUF_ l
+#   define __REDIRFROM_X(function, reentrant) \
+  function ## l ## reentrant
 #   ifdef __NO_LONG_DOUBLE_MATH
-#    define _MSUFTO_
+#    define __REDIRTO_X(function, reentrant) \
+   __ ## function ## reentrant ## _finite
 #   else
-#    define _MSUFTO_ l
+#    define __REDIRTO_X(function, reentrant) \
+   __ ## function ## l ## reentrant ## _finite
 #   endif
 #   include <bits/math-finite.h>
 #   undef _Mdouble_
 #   undef __MATH_DECLARING_DOUBLE
 #   undef __MATH_DECLARING_FLOATN
-#   undef _MSUF_
-#   undef _MSUFTO_
+#   undef __REDIRFROM_X
+#   undef __REDIRTO_X
 #  endif
 
 # endif /* __USE_ISOC99.  */
@@ -697,18 +704,21 @@ iszero (__T __val)
 #  define _Mdouble_ _Float128
 #  define __MATH_DECLARING_DOUBLE 0
 #  define __MATH_DECLARING_FLOATN 1
-#  define _MSUF_ f128
+#  define __REDIRFROM_X(function, reentrant) \
+  function ## f128 ## reentrant
 #  if __HAVE_DISTINCT_FLOAT128
-#   define _MSUFTO_ f128
+#   define __REDIRTO_X(function, reentrant) \
+   __ ## function ## f128 ## reentrant ## _finite
 #  else
-#   define _MSUFTO_ l
+#   define __REDIRTO_X(function, reentrant) \
+   __ ## function ## l ## reentrant ## _finite
 #  endif
 #  include <bits/math-finite.h>
 #  undef _Mdouble_
 #  undef __MATH_DECLARING_DOUBLE
 #  undef __MATH_DECLARING_FLOATN
-#  undef _MSUF_
-#  undef _MSUFTO_
+#  undef __REDIRFROM_X
+#  undef __REDIRTO_X
 # endif
 #endif /* __FINITE_MATH_ONLY__ > 0.  */