#23 inline/static function mismatch with SunPro 8 compiler

[grant beattie]

audio.c:audio_mulaw_round() and audio_mulaw_dither()
are declared as inline and call static functions
linear2mulaw() and mulaw2linear().

with SunPro 8, this causes a build error because inline
functions cannot call static functions unless they are
static *and* inline.

"audio.c", line 1033: reference to static identifier
"linear2mulaw" in extern inline function
"audio.c", line 1052: reference to static identifier
"linear2mulaw" in extern inline function
"audio.c", line 1055: reference to static identifier
"mulaw2linear" in extern inline function
cc: acomp failed for audio.c

the fix is to inline linear2mulaw() and mulaw2linear().
madplay can then be built and installed on Solaris with
SunPro.

[grant beattie]

inline two functions which called from inline functions