Replace handwritten Makefile with configure script

.gitignore

@@ -2,3 +2,4 @@ build/
 slcl
 *.o
 *.d
+Makefile

Makefile

@@ -1,51 +0,0 @@
-.POSIX:
-
-PREFIX = /usr/local
-DST = $(PREFIX)/bin
-PROJECT = slcl
-O = -Og
-CDEFS = -D_FILE_OFFSET_BITS=64 # Required for large file support on 32-bit.
-CFLAGS = $(O) $(CDEFS) -g -Wall -Ilibweb/include -Ilibweb/dynstr/include \
-	-MD -MF $(@:.o=.d)
-LIBS = -lcjson -lssl -lm -lcrypto
-DEPS = $(OBJECTS:.o=.d)
-DYNSTR = libweb/dynstr/libdynstr.a
-DYNSTR_FLAGS = -Llibweb/dynstr -ldynstr
-LIBWEB = libweb/libslweb.a
-SLWEB_FLAGS = -Llibweb -lweb
-OBJECTS = \
-	auth.o \
-	base64.o \
-	cftw.o \
-	hex.o \
-	jwt.o \
-	main.o \
-	page.o \
-	style.o
-
-all: $(PROJECT)
-
-install: all usergen
-	mkdir -p $(DST)
-	cp slcl usergen $(DST)
-	chmod 0755 $(DST)/slcl
-	chmod 0755 $(DST)/usergen
-	+cd doc && $(MAKE) PREFIX=$(PREFIX) install
-
-clean:
-	rm -f $(OBJECTS) $(DEPS)
-	+cd libweb && $(MAKE) clean
-	+cd libweb/dynstr && $(MAKE) clean
-
-FORCE:
-
-$(PROJECT): $(OBJECTS) $(DYNSTR) $(LIBWEB)
-	$(CC) $(OBJECTS) $(LDFLAGS) $(LIBS) $(SLWEB_FLAGS) $(DYNSTR_FLAGS) -o $@
-
-$(DYNSTR): FORCE
-	+cd libweb/dynstr && $(MAKE)
-
-$(LIBWEB): FORCE
-	+cd libweb && $(MAKE)
-
--include $(DEPS)

README.md

@@ -74,7 +74,8 @@ sudo apt install cmake xxd jq
 Two build environments are provided for `slcl` - feel free to choose any of
 them:
 
-- A mostly POSIX-compliant [`Makefile`](Makefile).
+- A [`configure`](configure) POSIX shell and mostly POSIX-compliant
+[`Makefile`](Makefile).
 - A [`CMakeLists.txt`](CMakeLists.txt).
 
 `slcl` can be built using the standard build process:
@@ -82,6 +83,7 @@ them:
 #### Make
 
 ```sh
+$ ./configure
 $ make
 ```
 

configure

@@ -0,0 +1,168 @@
+#! /bin/sh
+
+set -e
+
+default_prefix=/usr/local
+prefix=$default_prefix
+default_CC='c99'
+# FILE_OFFSET_BITS=64 is required for large file support on 32-bit platforms.
+default_CFLAGS='-O1 -g -D_FILE_OFFSET_BITS=64 -Wall -MD -MF $(@:.o=.d)'
+default_LDFLAGS="-lcjson -lssl -lm -lcrypto"
+
+CC=${CC:-$default_CC}
+CFLAGS=${CFLAGS:-"$default_CFLAGS $default_NPCFLAGS"}
+LDFLAGS=${LDFLAGS:-$default_LDFLAGS}
+
+help()
+{
+	cat <<-EOF
+$0 [OPTION ...]
+
+--prefix      Set installation directory [$default_prefix]
+
+Some influential environment variables:
+  CC                  C compiler [$default_CC]
+  CFLAGS              C compiler flags [$default_CFLAGS]
+  LDFLAGS             Link-time flags [$default_LDFLAGS]
+EOF
+}
+
+while true; do
+	split_arg=0
+
+	if printf "%s" "$1" | grep -e '=' > /dev/null
+	then
+		key="$(printf "%s" "$1" | cut -d '=' -f1)"
+		value="$(printf "%s" "$1" | cut -d '=' -f2)"
+		split_arg=1
+	else
+		key="$1"
+		value="$2"
+	fi
+
+	case "$key" in
+		--prefix ) prefix="$value"; shift; test $split_arg -eq 0 && shift ;;
+		-h | --help ) help; exit 0 ;;
+		* ) test "$1" != "" && help && exit 1 || break ;;
+	esac
+done
+
+if pkg-config dynstr
+then
+	in_tree_dynstr=0
+	CFLAGS="$CFLAGS $(pkg-config --cflags dynstr)"
+	LDFLAGS="$LDFLAGS $(pkg-config --libs dynstr)"
+else
+	echo "Info: dynstr not found. Using in-tree copy" >&2
+	in_tree_dynstr=1
+	CFLAGS="$CFLAGS -Ilibweb/dynstr/include"
+	LDFLAGS="$LDFLAGS -Llibweb/dynstr -ldynstr"
+fi
+
+if pkg-config libweb
+then
+	in_tree_libweb=0
+	CFLAGS="$CFLAGS $(pkg-config --cflags libweb)"
+	LDFLAGS="$LDFLAGS $(pkg-config --libs libweb)"
+else
+	echo "Info: libweb not found. Using in-tree copy" >&2
+	in_tree_libweb=1
+	CFLAGS="$CFLAGS -Ilibweb/include"
+	LDFLAGS="$LDFLAGS -Llibweb -lweb"
+fi
+
+cleanup()
+{
+	rm -f $F
+}
+
+F=/tmp/Makefile.slcl
+trap cleanup EXIT
+
+cat <<EOF > $F
+.POSIX:
+
+CC = $CC
+PREFIX = $prefix
+DST = $prefix/bin
+CFLAGS = $CFLAGS
+LDFLAGS = $LDFLAGS
+EOF
+
+cat <<"EOF" >> $F
+PROJECT = slcl
+DEPS = $(OBJECTS:.o=.d)
+OBJECTS = \
+	auth.o \
+	base64.o \
+	cftw.o \
+	hex.o \
+	jwt.o \
+	main.o \
+	page.o \
+	style.o
+
+all: $(PROJECT)
+
+install: all usergen
+	mkdir -p $(DST)
+	cp slcl usergen $(DST)
+	chmod 0755 $(DST)/slcl
+	chmod 0755 $(DST)/usergen
+	+cd doc && $(MAKE) PREFIX=$(PREFIX) install
+
+FORCE:
+
+$(PROJECT): $(OBJECTS)
+	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+EOF
+
+if [ $in_tree_dynstr -ne 0 ]
+then
+cat <<"EOF" >> $F
+DYNSTR = libweb/dynstr/libdynstr.a
+$(PROJECT): $(DYNSTR)
+$(DYNSTR): FORCE
+	+cd libweb/dynstr && $(MAKE) CC=$(CC)
+EOF
+fi
+
+if [ $in_tree_libweb -ne 0 ]
+then
+cat <<"EOF" >> $F
+LIBWEB = libweb/libslweb.a
+$(PROJECT): $(LIBWEB)
+$(LIBWEB): FORCE
+	+cd libweb && $(MAKE) CC=$(CC)
+EOF
+fi
+
+cat <<"EOF" >> $F
+clean:
+	rm -f $(OBJECTS) $(DEPS)
+EOF
+
+if [ $in_tree_dynstr -ne 0 ]
+then
+cat <<"EOF" >> $F
+	+cd libweb/dynstr && $(MAKE) clean
+EOF
+fi
+
+if [ $in_tree_libweb -ne 0 ]
+then
+cat <<"EOF" >> $F
+	+cd libweb && $(MAKE) clean
+EOF
+fi
+
+cat <<"EOF" >> $F
+distclean: clean
+	rm Makefile
+EOF
+
+cat <<"EOF" >> $F
+-include $(DEPS)
+EOF
+
+mv $F Makefile