configure: use system libbase58 if available.

Also one less headache for reproducible builds.  But unlike
libsodium, this only seems common in Ubuntu.

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

CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - JSON API: `listpeers` now includes `funding_allocation_msat`, which returns a map of the amounts initially funded to the channel by each peer, indexed by channel id.
 - `option_data_loss_protect` is now enabled by default.
 - JSON API: `help` with a `command` argument gives a JSON array, like other commands.
+- build: we'll use the system libbase58 and libsodium if found suitable.
 
 ### Deprecated
 

configure

@@ -171,6 +171,20 @@ int main(void)
 	exit(0);
 }
 /*END*/
+var=HAVE_SYSTEM_LIBBASE58
+desc=libbase58
+style=DEFINES_EVERYTHING|EXECUTE|MAY_NOT_COMPILE
+link=-lbase58
+code=
+#include <libbase58.h>
+#include <stdio.h>
+
+int main(void)
+{
+	printf("%p\n", b58check);
+	exit(0);
+}
+/*END*/
 EOF
 mv $CONFIG_VAR_FILE.$$ $CONFIG_VAR_FILE
 

doc/INSTALL.md

@@ -36,7 +36,8 @@ 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 zlib1g-dev libsodium
+      libsqlite3-dev python python3 net-tools zlib1g-dev libsodium \
+	  libbase58-dev
 
 If you don't have Bitcoin installed locally you'll need to install that
 as well:

external/Makefile

@@ -15,13 +15,12 @@ JSMN_HEADERS := external/jsmn/jsmn.h
 LIBBASE58_HEADERS := external/libbase58/libbase58.h
 
 EXTERNAL_HEADERS := $(LIBSODIUM_HEADERS) $(LIBWALLY_HEADERS) $(LIBSECP_HEADERS) $(JSMN_HEADERS) $(LIBBASE58_HEADERS)
-EXTERNAL_LIBS := external/libwallycore.a external/libsecp256k1.a external/libjsmn.a external/libbase58.a external/libbacktrace.a
+EXTERNAL_LIBS := external/libwallycore.a external/libsecp256k1.a external/libjsmn.a external/libbacktrace.a
 
 EXTERNAL_INCLUDE_FLAGS :=					\
 	-I external/libwally-core/include/			\
 	-I external/libwally-core/src/secp256k1/include/	\
 	-I external/jsmn/					\
-	-I external/libbase58/					\
 	-I external/libbacktrace/				\
 	-I external/libbacktrace-build
 
@@ -32,6 +31,13 @@ else
 LDLIBS += -lsodium
 endif
 
+ifneq ($(HAVE_SYSTEM_LIBBASE58),1)
+EXTERNAL_INCLUDE_FLAGS += -I external/libbase58/
+EXTERNAL_LIBS +=  external/libbase58.a
+else
+LDLIBS += -lbase58
+endif
+
 EXTERNAL_LDLIBS := -Lexternal $(patsubst lib%.a,-l%,$(notdir $(EXTERNAL_LIBS)))
 
 submodcheck: FORCE