Fix warnings for -Wmissing-prototypes

Add -Wmissing-prototypes if compiling with gcc
Static where possible

git-svn-id: https://svn.musicpd.org/mpd/trunk@4657 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/inputStream_http.h

@@ -21,7 +21,7 @@
 
 #include "inputStream.h"
 
-void inputStream_initHttp();
+void inputStream_initHttp(void);
 
 int inputStream_httpOpen(InputStream * inStream, char *filename);