solo-c/Makefile

# Makefile for Solo-C.
#
# Written for the POSIX make utility (IEEE Std 1003.1, XCU make) and a POSIX
# shell (/bin/sh), so it works with any conforming make and no GNU-only
# features. Deliberately avoided:
#
#   $(shell ...)     not POSIX - pkg-config is run by the recipe shell
#   ?=               not POSIX - defaults are plain "=" and are overridden on
#                           the command line, e.g. make CC=clang CFLAGS=-O1
#   .PHONY           not POSIX - see the FORCE target at the bottom
#   target-specific variables, ifeq, wildcard, -include, ... all non-POSIX
#
# Rule syntax used here: recipe lines start with a TAB, macros are written
# $(NAME) (POSIX also accepts ${NAME}), and the only automatic macro used is
# $@, the name of the target. Prerequisite names are written out: $< is POSIX
# for inference rules only, and "$< is the first prerequisite" in a plain rule
# is a GNU extension that even BusyBox make lacks.

SHELL = /bin/sh

# Standard macros. POSIX defaults CC to c99; Solo-C uses the system compiler
# driver "cc" instead, which is the compiler a platform actually ships
# (gcc, clang, musl-gcc, ...). Every macro here can be overridden from the
# command line: make CC=clang, make CFLAGS=-O1, make LDLIBS=-lcurl.
CC = cc
CFLAGS = -Wall -Wextra -O2 -std=c99 -march=native
LDFLAGS =
LDLIBS =
LINT = lint
LINTFLAGS =
LINTLIBS = -lc

# Link-time discovery of the shared dependencies. POSIX make cannot run
# commands while reading a makefile, so the flags are collected by the shell
# that runs the recipe instead of by $(shell ...) while parsing.
PKG_CONFIG = pkg-config
PKGS = libcurl json-c readline
# $$(...) survives expansion of the macro and reaches the shell as $(...).
PKG_CFLAGS = $$($(PKG_CONFIG) --cflags $(PKGS))
PKG_LIBS = $$($(PKG_CONFIG) --libs $(PKGS))

# Fully static binary.
#
# The distro libcurl.a cannot be linked statically on Alpine: it pulls in
# libpsl, libbrotli, libzstd and libnghttp2, whose static archives hold LTO
# bytecode from GCC 14 that the installed GCC 15 cannot read ("bytecode
# stream ... generated with LTO version 14.0 instead of the expected 15.1"),
# so psl_*/Brotli*/ZSTD* never resolve. -fno-lto does not help; the objects
# are bytecode, not C.
#
# static-deps/libcurl.a is curl built without those four libraries, leaving
# only LTO-free static deps. Regenerate with: make static-deps
#
# c-ares is built from source by the same script, for two reasons: a minimal
# system often has no libcares.a at all (Void's c-ares-devel ships the shared
# library only), and where an archive does exist it can carry the same LTO
# bytecode as the distro libcurl.a. Building it also pins the version.
#
# Archive order matters: libcurl.a pulls in ares_* symbols, so libcares.a has to
# come after it on the link line.
CURL_STATIC = static-deps/libcurl.a
CARES_STATIC = static-deps/libcares.a
STATIC_LIBS = $(CURL_STATIC) $(CARES_STATIC) -lssl -lcrypto -lz -lidn2 -lunistring \
	-lreadline -lncursesw -ljson-c -lm -ldl -pthread

solo: main.c
	$(CC) $(CFLAGS) $(PKG_CFLAGS) $(LDFLAGS) -o $@ main.c $(PKG_LIBS) $(LDLIBS)
	strip $@

# Writes solo-static, not a file called "static", so $@ is not used here.
static: main.c
	@for f in $(CURL_STATIC) $(CARES_STATIC); do \
		test -f $$f || { echo "missing $$f - run: make static-deps"; exit 1; }; \
	done
	$(CC) $(CFLAGS) $(LDFLAGS) -fno-lto -static -o solo-static main.c $(STATIC_LIBS) $(LDLIBS)
	strip solo-static

static-deps: FORCE
	sh ./mkstaticdeps.sh

# Rebuild both archives from scratch, ignoring what is already there.
static-deps-force: FORCE
	FORCE=1 sh ./mkstaticdeps.sh

# Install paths. DESTDIR and PREFIX may be set on the command line:
# make install DESTDIR=/tmp/pkg PREFIX=/usr
PREFIX = /usr/local
BINDIR = $(PREFIX)/bin
INSTALL = install

install: solo FORCE
	$(INSTALL) -d $(DESTDIR)$(BINDIR)
	$(INSTALL) -m 755 solo $(DESTDIR)$(BINDIR)/solo

uninstall: FORCE
	rm -f $(DESTDIR)$(BINDIR)/solo $(DESTDIR)$(BINDIR)/solo-static

clean: FORCE
	rm -f solo solo-static

# POSIX lint target: runs the lint tool named by the LINT macro.
lint: main.c FORCE
	$(LINT) $(LINTFLAGS) $(LINTLIBS) main.c

# POSIX make has no .PHONY special target. Any target that depends on FORCE is
# always out of date, because FORCE never creates a file, so its recipe always
# runs. Keep this target last: the first target in the file is the default goal.
FORCE:
	@: