zlib: add as a requirement.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Makefile

@@ -175,7 +175,7 @@ CFLAGS = $(CPPFLAGS) $(CWARNFLAGS) $(CDEBUGFLAGS) -I $(CCANDIR) $(EXTERNAL_INCLU
 CONFIGURATOR_CC := $(CC)
 
 LDFLAGS = $(PIE_LDFLAGS)
-LDLIBS = -L/usr/local/lib -lm -lgmp -lsqlite3 $(COVFLAGS)
+LDLIBS = -L/usr/local/lib -lm -lgmp -lsqlite3 -lz $(COVFLAGS)
 
 default: all-programs all-test-programs
 

README.md

@@ -58,7 +58,7 @@ For the impatient here's the gist of it for Ubuntu and Debian:
     sudo apt-get update
     sudo apt-get install -y \
       autoconf automake build-essential git libtool libgmp-dev \
-      libsqlite3-dev python python3 net-tools
+      libsqlite3-dev python python3 net-tools zlib1g-dev
     git clone https://github.com/ElementsProject/lightning.git
     cd lightning
     make

doc/INSTALL.md

@@ -15,6 +15,7 @@ Library Requirements
 You will need several development libraries:
 * libsqlite3: for database support.
 * libgmp: for secp256k1
+* zlib: for compression routines.
 
 For actually doing development and running the tests, you will also need:
 * pip3: to install python-bitcoinlib
@@ -34,7 +35,7 @@ Get dependencies:
     sudo apt-get update
     sudo apt-get install -y \
       autoconf automake build-essential git libtool libgmp-dev \
-      libsqlite3-dev python python3 net-tools
+      libsqlite3-dev python python3 net-tools zlib1g-dev
 
 If you don't have Bitcoin installed locally you'll need to install that
 as well: