PATCH: Apply Nathan's macro trick

[Loren James Rittle]

This is the final form of <cmath> for the time being (related to
dynamic visible) and the binding form I will use in <cstdio>,
<cstdlib>, <cwchar>.  I thought a few moments about actually combining
both macro-enabled paths in __c99_binding together, ala:

  _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_ACOSF, acosf, float (acosf)(float));

But I couldn't convince myself the extra complexity was worth it.  I
also fixed an oversight with dynamic C99 FP macro capture (related to
the dynamic wrapper I added, not the original code).  If someone says
not to capture, then we shouldn't touch the C99 FP macro names.  Also,
this might allow for a practical workaround to getting old code to
compile without having to edit the user's source.  No regressions
(hand-checked -E output with various hand-setup cases).  I will commit
next time I have access.

	* include/c_std/std_cmath.h (__gnu_cxx::__c99_binding): Rework
	to use Nathan's macro trick.
	(C99 FP capture): Only undefine, if captured.

Index: libstdc++-v3/include/c_std/std_cmath.h
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/include/c_std/std_cmath.h,v
retrieving revision 1.7
diff -c -r1.7 std_cmath.h
*** libstdc++-v3/include/c_std/std_cmath.h	15 Apr 2003 07:27:54 -0000	1.7
--- libstdc++-v3/include/c_std/std_cmath.h	17 Apr 2003 09:33:08 -0000
***************
*** 76,81 ****
--- 76,86 ----
  #undef tan
  #undef tanh
  
+ #define _GLIBCXX_C99_USING_0(__b, __c) __c
+ #define _GLIBCXX_C99_USING_1(__b, __c) __b
+ #define _GLIBCXX_C99_USING(__a,__b,__c) _GLIBCXX_C99_USING_ ## __a(__b, __c)
+ #define _GLIBCXX_C99_BIND(__a,__b) _GLIBCXX_C99_USING(__a, using ::__b;, )
+ 
  // ...and in the darkness bind them...
  namespace __gnu_cxx
  {
***************
*** 103,162 ****
      extern "C" float (tanhf)(float);
  #endif
  #if !_GLIBCPP_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC
! #if _GLIBCPP_HAVE_ACOSF
!     using ::acosf;
! #endif
! #if _GLIBCPP_HAVE_ASINF
!     using ::asinf;
! #endif
! #if _GLIBCPP_HAVE_ATANF
!     using ::atanf;
! #endif
! #if _GLIBCPP_HAVE_ATAN2F
!     using ::atan2f;
! #endif
! #if _GLIBCPP_HAVE_CEILF
!     using ::ceilf;
! #endif
! #if _GLIBCPP_HAVE_COSHF
!     using ::coshf;
! #endif
! #if _GLIBCPP_HAVE_EXPF
!     using ::expf;
! #endif
! #if _GLIBCPP_HAVE_FLOORF
!     using ::floorf;
! #endif
! #if _GLIBCPP_HAVE_FMODF
!     using ::fmodf;
! #endif
! #if _GLIBCPP_HAVE_FREXPF
!     using ::frexpf;
! #endif
! #if _GLIBCPP_HAVE_LDEXPF
!     using ::ldexpf;
! #endif
! #if _GLIBCPP_HAVE_LOGF
!     using ::logf;
! #endif
! #if _GLIBCPP_HAVE_LOG10F
!     using ::log10f;
! #endif
! #if _GLIBCPP_HAVE_MODFF
!     using ::modff;
! #endif
! #if _GLIBCPP_HAVE_POWF
!     using ::powf;
! #endif
! #if _GLIBCPP_HAVE_SINHF
!     using ::sinhf;
! #endif
! #if _GLIBCPP_HAVE_TANF
!     using ::tanf;
! #endif
! #if _GLIBCPP_HAVE_TANHF
!     using ::tanhf;
! #endif
  #endif /* _GLIBCPP_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC */
    }
  }
--- 108,131 ----
      extern "C" float (tanhf)(float);
  #endif
  #if !_GLIBCPP_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_ACOSF, acosf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_ASINF, asinf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_ATANF, atanf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_ATAN2F, atan2f)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_CEILF, ceilf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_COSHF, coshf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_EXPF, expf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_FLOORF, floorf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_FMODF, fmodf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_FREXPF, frexpf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_LDEXPF, ldexpf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_LOGF, logf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_LOG10F, log10f)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_MODFF, modff)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_POWF, powf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_SINHF, sinhf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_TANF, tanf)
!     _GLIBCXX_C99_BIND (_GLIBCPP_HAVE_TANHF, tanhf)
  #endif /* _GLIBCPP_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC */
    }
  }
***************
*** 646,655 ****
       int 
       __capture_isunordered(_Tp __f1, _Tp __f2) 
       { return isunordered(__f1, __f2); }
! } 
! #endif /* _GLIBCPP_USE_C99_FP_MACROS_DYNAMIC */
! #endif
  
  #undef fpclassify
  #undef isfinite
  #undef isinf
--- 615,623 ----
       int 
       __capture_isunordered(_Tp __f1, _Tp __f2) 
       { return isunordered(__f1, __f2); }
! }
  
+ // Only undefine the C99 FP macros, if actually captured for namespace movement
  #undef fpclassify
  #undef isfinite
  #undef isinf
***************
*** 662,667 ****
--- 630,637 ----
  #undef islessequal
  #undef islessgreater
  #undef isunordered
+ #endif /* _GLIBCPP_USE_C99_FP_MACROS_DYNAMIC */
+ #endif
  
  #if _GLIBCPP_USE_C99
  #if !_GLIBCPP_USE_C99_FP_MACROS_DYNAMIC