png is a standard static lib, provide it

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@6027 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/libs/png/Jamfile

@@ -21,3 +21,24 @@ SharedLibrary png :
 	pngwtran.c
 	pngwutil.c
 : z ;
+
+StaticLibrary png : 
+	png.c
+	pngerror.c
+	pnggccrd.c
+	pngget.c
+	pngmem.c
+	pngpread.c
+	pngread.c
+	pngrio.c
+	pngrtran.c
+	pngrutil.c
+	pngset.c
+	pngtrans.c
+	pngvcrd.c
+	pngwio.c
+	pngwrite.c
+	pngwtran.c
+	pngwutil.c
+: STATIC_LIBRARY_DIR
+;