Remove the -D option from install

In the Makefile, `make install` is used to create missing directories
and install files into them. Until now, the -D option was used for this
job. However, FreeBSD as an implementation of the install command that
differs about this option. In order to remain compatible with FreeBSD,
the -D option has been removed and replace by prior directory creation
using the -d option, which is common to (most?) implementations.
https://www.freebsd.org/cgi/man.cgi?query=install
https://man.openbsd.org/install
https://linux.die.net/man/1/install

Makefile

@@ -3,6 +3,8 @@ EXEC_PREFIX = $(PREFIX)
 BINDIR = $(EXEC_PREFIX)/bin
 DATAROOTDIR = $(PREFIX)/share
 DATADIR = $(DATAROOTDIR)
+MAN5DIR = $(DATADIR)/man/man5
+MAN8DIR = $(DATADIR)/man/man8
 SYSCONFDIR = /etc
 TARGET_DIR = ./target/release
 MAN_SRC_DIR = ./man/en
@@ -28,15 +30,18 @@ man:
 	gzip <"$(MAN_SRC_DIR)/tacd.8" >"$(MAN_DST_DIR)/tacd.8.gz"
 
 install:
-	install -D -m 0755 $(TARGET_DIR)/acmed $(DESTDIR)$(BINDIR)/acmed
-	install -D -m 0755 $(TARGET_DIR)/tacd $(DESTDIR)$(BINDIR)/tacd
-	install -D -m 0644 $(TARGET_DIR)/man/acmed.8.gz $(DESTDIR)$(DATADIR)/man/man8/acmed.8.gz
-	install -D -m 0644 $(TARGET_DIR)/man/acmed.toml.5.gz $(DESTDIR)$(DATADIR)/man/man5/acmed.toml.5.gz
-	install -D -m 0644 $(TARGET_DIR)/man/tacd.8.gz $(DESTDIR)$(DATADIR)/man/man8/tacd.8.gz
-	install -D -m 0644 acmed/config/acmed.toml $(DESTDIR)$(SYSCONFDIR)/acmed/acmed.toml
-	install -D -m 0644 acmed/config/default_hooks.toml $(DESTDIR)$(SYSCONFDIR)/acmed/default_hooks.toml
-	install -d -m 0700 $(DESTDIR)$(SYSCONFDIR)/acmed/accounts
+	install -d -m 0755 $(DESTDIR)$(BINDIR)
+	install -d -m 0755 $(DESTDIR)$(MAN5DIR)
+	install -d -m 0755 $(DESTDIR)$(MAN8DIR)
 	install -d -m 0755 $(DESTDIR)$(SYSCONFDIR)/acmed/certs
+	install -d -m 0700 $(DESTDIR)$(SYSCONFDIR)/acmed/accounts
+	install -m 0755 $(TARGET_DIR)/acmed $(DESTDIR)$(BINDIR)/acmed
+	install -m 0755 $(TARGET_DIR)/tacd $(DESTDIR)$(BINDIR)/tacd
+	install -m 0644 $(TARGET_DIR)/man/acmed.8.gz $(DESTDIR)$(MAN8DIR)/acmed.8.gz
+	install -m 0644 $(TARGET_DIR)/man/acmed.toml.5.gz $(DESTDIR)$(MAN5DIR)/acmed.toml.5.gz
+	install -m 0644 $(TARGET_DIR)/man/tacd.8.gz $(DESTDIR)$(MAN8DIR)/tacd.8.gz
+	install -m 0644 acmed/config/acmed.toml $(DESTDIR)$(SYSCONFDIR)/acmed/acmed.toml
+	install -m 0644 acmed/config/default_hooks.toml $(DESTDIR)$(SYSCONFDIR)/acmed/default_hooks.toml
 
 clean:
 	cargo clean