https://bugs.gentoo.org/705372

if you use use-flag oss,
this will fix on gcc-9.x
error: call of overloaded abs(unsigned int) is ambiguous

Signed-off-by: Joerg Bornkessel <hd_brummy@gentoo.org> ( 14 Jan 2020 )
diff -Naur mp3ng-0.9.13-MKIV-pre3.orig/player-mp3.c mp3ng-0.9.13-MKIV-pre3/player-mp3.c
--- mp3ng-0.9.13-MKIV-pre3.orig/player-mp3.c	2020-01-14 22:33:44.687155745 +0100
+++ mp3ng-0.9.13-MKIV-pre3/player-mp3.c	2020-01-14 22:35:25.490155745 +0100
@@ -1435,7 +1435,7 @@
         int real=sr;
         CHECK(ioctl(fd,SNDCTL_DSP_SPEED,&real));
         d(printf("oss: DSP samplerate now %d\n",real))
-        if(abs(real-sr)<sr/50) {
+        if(std::abs( int(real-sr) )<sr/50) {
           outSr=sr;
           d(printf("mp3-oss: DSP reset done\n"))
           return true;