Use docker to build static releases

Static builds are possible with the musl C library.
glibc is capricious when it comes to static linking and DNS support (and
other things).

Dockerfile

@@ -0,0 +1,27 @@
+FROM alpine:3.10
+
+WORKDIR /build
+
+RUN apk add --no-cache wget cmake make gcc g++ linux-headers zlib-dev openssl-dev \
+            automake autoconf libevent-dev ncurses-dev msgpack-c-dev libexecinfo-dev \
+            ncurses-static libexecinfo-static libevent-static msgpack-c ncurses-libs \
+            libevent libexecinfo openssl zlib
+
+RUN set -ex; \
+	mkdir -p /src/libssh/build; \
+	cd /src; \
+	wget -O libssh.tar.xz https://www.libssh.org/files/0.9/libssh-0.9.0.tar.xz; \
+	tar -xf libssh.tar.xz -C /src/libssh --strip-components=1; \
+	cd /src/libssh/build; \
+	cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr \
+                -DWITH_SFTP=OFF -DWITH_SERVER=OFF -DWITH_PCAP=OFF \
+                -DWITH_STATIC_LIB=ON -DWITH_GSSAPI=OFF ..; \
+	make -j $(nproc); \
+	make install
+
+COPY . .
+
+RUN ./autogen.sh
+RUN ./configure --enable-static
+RUN make -j $(nproc)
+RUN strip tmate

Makefile.static-build

@@ -1,61 +0,0 @@
-LIBSSH=libssh-0.7.2
-LIBSSH_URL=https://red.libssh.org/attachments/download/177/$(LIBSSH).tar.xz
-LIBSSH_LIB=ext/lib/libssh.a
-
-MSGPACK=msgpack-1.3.0
-MSGPACK_URL=https://github.com/msgpack/msgpack-c/releases/download/cpp-1.3.0/$(MSGPACK).tar.gz
-MSGPACK_LIB=ext/lib/libmsgpack.a
-
-TMATE_CONFIGURE=PKG_CONFIG_PATH=./ext/lib/pkgconfig
-
-LIBC=$(shell gcc -print-file-name=libc.a)
-STATIC_LIBC_OBJECTS=fdelt_chk
-STATIC_COMPAT_OBJECTS=memcpy clock_gettime
-
-all: tmate
-
-dependencies:
-	apt-get install build-essential cmake libssl-dev autoconf automake pkg-config libtool libevent-dev libncurses-dev zlib1g-dev
-
-downloads/$(notdir $(LIBSSH_URL)):
-	mkdir -p downloads
-	wget -O $@ $(LIBSSH_URL)
-
-$(LIBSSH)/.ready: downloads/$(notdir $(LIBSSH_URL))
-	tar xf $<
-	touch $@
-
-downloads/$(notdir $(MSGPACK_URL)):
-	mkdir -p downloads
-	wget -O $@ $(MSGPACK_URL)
-
-$(MSGPACK)/.ready: downloads/$(notdir $(MSGPACK_URL))
-	tar xf $<
-	touch $@
-
-$(LIBSSH_LIB): $(LIBSSH)/.ready
-	mkdir -p $(LIBSSH)/build
-	cd $(LIBSSH)/build; ([ -f Makefile ] || cmake -DCMAKE_INSTALL_PREFIX:PATH=$(shell pwd)/ext .. -DWITH_SFTP=OFF -DWITH_SERVER=OFF -DWITH_PCAP=OFF -DWITH_STATIC_LIB=ON -DWITH_GSSAPI=OFF)
-	+make -C $(LIBSSH)/build install
-
-$(MSGPACK_LIB): $(MSGPACK)/.ready
-	mkdir -p $(MSGPACK)/build
-	cd $(MSGPACK)/build; ([ -f Makefile ] || cmake -DCMAKE_INSTALL_PREFIX:PATH=$(shell pwd)/ext ..)
-	+make -C $(MSGPACK)/build install
-
-libc/%.o:
-	mkdir -p libc
-	cd libc; ar x $(LIBC) $(notdir $@)
-
-compat/%.o: compat/%.c
-	gcc -c -o $@ $<
-
-tmate: $(MSGPACK_LIB) $(LIBSSH_LIB) $(patsubst %,libc/%.o,$(STATIC_LIBC_OBJECTS)) $(patsubst %,compat/%.o,$(STATIC_COMPAT_OBJECTS))
-	./autogen.sh
-	$(TMATE_CONFIGURE) ./configure --enable-static
-	+make
-	strip tmate
-
-clean:
-	rm -rf ext libc $(LIBSSH) $(MSGPACK)
-	+make clean

compat/clock_gettime.c

@@ -1,9 +0,0 @@
-#define _GNU_SOURCE
-#include <time.h>
-#include <unistd.h>
-#include <sys/syscall.h>
-
-int clock_gettime(clockid_t clk_id, struct timespec *tp)
-{
-	return syscall(SYS_clock_gettime, clk_id, tp);
-}

compat/memcpy.c

@@ -1,11 +0,0 @@
-// http://stackoverflow.com/questions/8823267/linking-against-older-symbol-version-in-a-so-file
-
-#include <string.h>
-
-/* some systems do not have newest memcpy@@GLIBC_2.14 - stay with old good one */
-asm (".symver memcpy, memcpy@GLIBC_2.2.5");
-
-void *__wrap_memcpy(void *dest, const void *src, size_t n)
-{
-    return memcpy(dest, src, n);
-}

configure.ac

@@ -47,10 +47,11 @@ AC_ARG_ENABLE(
 	found_static=$enable_static
 )
 if test "x$found_static" = xyes; then
+        # XXX Static build are only doable with the musl library
 	PKG_CONFIG="pkg-config --static"
 
 	CFLAGS="$CFLAGS -flto"
-	LDFLAGS="$LDFLAGS -flto"
+	LDFLAGS="$LDFLAGS -flto -static -no-pie"
 
 	PKG_CHECK_MODULES([ZLIB], [zlib], [
 		CPPFLAGS="$ZLIB_CFLAGS $CPPFLAGS"
@@ -61,7 +62,6 @@ if test "x$found_static" = xyes; then
 		CPPFLAGS="$LIBCRYPTO_CFLAGS $CPPFLAGS"
 		LIBS="$LIBCRYPTO_LIBS $LIBS"
 	])
-  # See more static settings below... (search for found_static)
 fi
 
 # Is this gcc?
@@ -462,17 +462,6 @@ if test "x$found_getopt" != xno; then
 fi
 AM_CONDITIONAL(NO_GETOPT, [test "x$found_getopt" = xno])
 
-if test "x$found_static" = xyes; then
-	# libc and libdl should be dynamically linked.
-	# but we want to lower our requirements for libc's version.
-	# so we extract some symobls and add them here
-	if test `uname -m` = x86_64; then
-		LIBS="compat/memcpy.o -Wl,--wrap=memcpy $LIBS"
-	fi
-	LIBS="compat/clock_gettime.o libc/fdelt_chk.o $LIBS"
-	LIBS="-Wl,-Bstatic ${LIBS/-ldl/} -Wl,-Bdynamic -ldl"
-fi
-
 # Check for BSD-style integer types.
 AC_MSG_CHECKING(for BSD-style unsigned types)
 AC_COMPILE_IFELSE([AC_LANG_SOURCE(