tools: holemap: new tool

Tool to list how a file is 'sparse' and calculate how 'sparse' it
/could/ be.

Signed-off-by: Michel Pollet <buserror@gmail.com>

tools/Makefile

@@ -0,0 +1,15 @@
+
+CPPFLAGS = -Wall -I../src/server -I../src/common -I../src/proxy \
+			-Doff64_t=__off64_t \
+			-Wunused-const-variable=0 -Wformat=0
+		
+CFLAGS = $(CPPFLAGS) -g -O3 -std=gnu99
+
+all: holemap
+
+# holemap requires libmhash-dev for md5 calculation
+holemap: holemap.c ../src/server/*.h
+	$(CC) $(CFLAGS) -o $@ $^ ${shell pkg-config mhash --cflags --libs}
+
+clean:
+	rm -f holemap