mpg123: Fix pkg-config file installation
mpg123: Fix pkg-config file installation

koletzky/haikuports,koletzky/haikuports,moochris/haikuports,miqlas/haikuports,Begasus/haikuports,Begasus/haikuports,haikuports/haikuports,moochris/haikuports,Begasus/haikuports,nielx/haikuports,koletzky/haikuports,miqlas/haikuports,nielx/haikuports,Begasus/haikuports,haikuports/haikuports,haikuports/haikuports,moochris/haikuports,nielx/haikuports,Begasus/haikuports,miqlas/haikuports,haikuports/haikuports,haikuports/haikuports