Why *l math functions are just skipped for some targets?

[Sergey Dmitrouk <sdmitrouk@accesssoftek.com>]

Hi,

files like __fpclassifyl.c omit implementation for corresponding
functions on platforms where sizeof(long double) == sizeof(double).
This is fine when musl is compiled at least with -O1 and compiler
omits calls to non-existing functions, but if one builds debug version
without optimizations, some executables end up having unresolved symbols
for functions like __fpclassifyl().

This causes some inconvenience.  Also, optimizing compilers are not
intended to allow such hacks, it just happens to be so.  Is there any
reason to not provide some stub functions?  I can image small size is
the reason, but not sure it justifies unexpected unresolved symbols.  At
least a comment in place of absent functions would be helpful.

Best regards,
Sergey