Makefile: Beautify compilation messages

This patch adds the --disable-verbose-compile switch to the
configure script.

When this option is used it reduces the verbosity of compilation
messages to the essential. However compiler warnings are not affected
and thus gain visibility by not standing in the middle of a storm
of other messages.

In summary, the compilation messages are reduced to a stream of

CC array.o
CC bagtree.o
CC configuration.o
CC connection.o
CC data.o
[...]

instead of a mind-boggling flux of

gcc -DHAVE_CONFIG_H -I. -I../src -I../WINGs/WINGs -I../wrlib -I../src
-I/usr/include/freetype2   -I/usr/local/include
-DLOCALEDIR=\"/usr/local/lib/loca\"/usr/local/share/WINGs\"
-DDEBUG  -fno-strict-aliasing -g -O2 -c array.c
gcc -DHAVE_CONFIG_H -I. -I../src -I../WINGs/WINGs
-I../wrlib -I../src -I/usr/include/freetype2   -I/usr/local/include
-DLOCALEDIR=\"/usr/local/lib/loca\"/usr/local/share/WINGs\"
-DDEBUG  -fno-strict-aliasing -g -O2 -c bagtree.c
[...]

src/Makefile.am

@@ -134,3 +134,13 @@ wmaker_LDADD = \
 #	@INTLIBS@ \
 #	@DLLIBS@
 
+LIBTOOL = $(QUIET) $(SHELL) $(top_srcdir)/libtool $(LIBTOOL_ARG)
+
+.c.o:
+	$(QUIET)$(COMPILE) -c $<
+
+.c.obj:
+	$(QUIET)$(COMPILE) -c `$(CYGPATH_W) '$<'`
+
+.c.lo:
+	$(QUIET)$(LTCOMPILE) -c -o $@ $<