Add a proper build system

FossilOrigin-Name: 3bac4aa7d3604e08794a83ca9017fe0a21c33382b41a733325f2f969f3dc5e91

configure.ac

@@ -0,0 +1,56 @@
+AC_INIT(ObjIRC, 0.1, js@heap.zone)
+BUILDSYS_INIT
+
+AC_CONFIG_SRCDIR(src)
+AC_CONFIG_MACRO_DIR(m4)
+AC_CONFIG_AUX_DIR(build-aux)
+
+AC_CHECK_TOOL(OBJFW_CONFIG, objfw-config)
+AS_IF([test x"$OBJFW_CONFIG" = x""], [
+       AC_MSG_ERROR(You need ObjFW and objfw-config installed!)
+])
+
+test x"$OBJC" = x"" && OBJC="$($OBJFW_CONFIG --objc)"
+
+AC_LANG([Objective C])
+AC_PROG_OBJC
+AC_PROG_OBJCPP
+AC_PROG_LN_S
+AC_PROG_INSTALL
+AC_PATH_TOOL(AR, ar)
+AC_PROG_RANLIB
+
+CPP="$OBJCPP"
+CPPFLAGS="$CPPFLAGS $OBJCPPFLAGS $($OBJFW_CONFIG --cppflags)"
+OBJCFLAGS="$OBJCFLAGS -Wall $($OBJFW_CONFIG --objcflags)"
+LDFLAGS="$LDFLAGS $($OBJFW_CONFIG --ldflags --rpath)"
+LIBS="$LIBS $($OBJFW_CONFIG --libs)"
+
+AC_ARG_ENABLE(shared,
+	AS_HELP_STRING([--disable-shared], [do not build shared library]))
+AS_IF([test x"$enable_shared" != x"no"], [
+	BUILDSYS_SHARED_LIB
+	AC_SUBST(OBJIRC_SHARED_LIB, "${LIB_PREFIX}objirc${LIB_SUFFIX}")
+], [
+	AC_SUBST(LIBOBJIRC_DEP, "../src/libobjirc.a")
+])
+AC_ARG_ENABLE(static, AS_HELP_STRING([--enable-static], [build static library]))
+AS_IF([test x"$enable_static" = x"yes" -o x"$enable_shared" = x"no"], [
+	AC_SUBST(OBJIRC_STATIC_LIB, "libobjirc.a")
+])
+
+AS_IF([test x"$GOBJC" = x"yes"], [
+	OBJCFLAGS="$OBJCFLAGS -Wwrite-strings -Wpointer-arith -Werror"
+])
+
+dnl We don't call AC_PROG_CPP, but only AC_PROG_OBJCPP and set CPP to OBJCPP
+dnl and add OBJCPPFLAGS to CPPFLAGS, thus we need to AC_SUBST these ourself.
+AC_SUBST(CPP)
+AC_SUBST(CPPFLAGS)
+
+AS_IF([test x"$cross_compiling" != x"yes"], [
+	AC_SUBST(RUN_TESTS, "run")
+])
+
+AC_CONFIG_FILES([buildsys.mk extra.mk])
+AC_OUTPUT