Quote path expression to take care of $(prefix) possibly containing spaces.

Originally committed as revision 3821 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/Makefile

@@ -306,7 +306,7 @@ install:
 endif
 
 installlib: all install-headers
-	install -m 644 $(LIB) $(prefix)/lib
+	install -m 644 $(LIB) "$(prefix)/lib"
 
 install-headers:
 	mkdir -p "$(prefix)/include/ffmpeg"

libavformat/Makefile

@@ -125,7 +125,7 @@ install:
 endif
 
 installlib: all install-headers
-	install -m 644 $(LIB) $(prefix)/lib
+	install -m 644 $(LIB) "$(prefix)/lib"
 
 install-headers:
 	mkdir -p "$(prefix)/include/ffmpeg"