[Bug libstdc++/86553] libstdc++-v3 build failure on AIX 5.3

[bugzilla-gcc at thewrittenword dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86553

--- Comment #9 from The Written Word <bugzilla-gcc at thewrittenword dot com> 
---
(In reply to Jonathan Wakely from comment #7)
> As I suspected, something is doing:
> 
> #define fabsl(X) fabs((double) (X))
> #define acosl(X) acos((double) (X))
> etc.

/usr/include/math.h on this platform has:
#ifdef _ISOC99_SOURCE
#ifdef __LONGDOUBLE128
...
#else
...
#define acosl(__x)              acos((double) (__x))
#define fabsl(__x)              fabs((double) (__x))
...
#endif