Make Berkley DB an optional dependency.

It doesn't seem necessary for any of the basic functionality.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

README

@@ -61,7 +61,7 @@ isync executable still exists; it is a compatibility wrapper around mbsync.
 
 * Requirements
 
-    Berkley DB 4.2+
+    Berkley DB 4.2+ (optional)
     OpenSSL for TLS/SSL support (optional)
 
 * Installation

configure.ac

@@ -146,8 +146,9 @@ AC_CACHE_CHECK([for Berkley DB >= 4.2], ac_cv_berkdb4,
 	        db->truncate(db, 0, 0, 0);
 	        db->open(db, 0, "foo", "foo", DB_HASH, DB_CREATE, 0)],
 	       [ac_cv_berkdb4=yes])])
-if test "x$ac_cv_berkdb4" = xno; then
+if test "x$ac_cv_berkdb4" = xyes; then
-  AC_MSG_ERROR([Berkley DB >= 4.2 not found.])
+  AC_SUBST([DB_LIBS], ["-ldb"])
+  AC_DEFINE(USE_DB, 1, [if Berkley DB should be used])
 fi
 
 have_zlib=
@@ -165,7 +166,8 @@ AC_ARG_ENABLE(compat,
 if test "x$ob_cv_enable_compat" != xno; then
   AC_CHECK_FUNCS(getopt_long)
 fi
-AM_CONDITIONAL(with_compat, test "x$ob_cv_enable_compat" != xno)
+AM_CONDITIONAL(with_compat, test "x$ob_cv_enable_compat" != xno -a "x$ac_cv_berkdb4" = xyes)
+AM_CONDITIONAL(with_mdconvert, test "x$ac_cv_berkdb4" = xyes)
 
 AC_CONFIG_FILES([Makefile src/Makefile src/compat/Makefile isync.spec])
 AC_OUTPUT
@@ -186,4 +188,9 @@ if test -n "$have_zlib"; then
 else
     AC_MSG_RESULT([Not using zlib])
 fi
+if test "x$ac_cv_berkdb4" = xyes; then
+    AC_MSG_RESULT([Using Berkley DB])
+else
+    AC_MSG_RESULT([Not using Berkley DB])
+fi
 AC_MSG_RESULT()

src/Makefile.am

@@ -3,20 +3,23 @@ compat_dir = compat
 endif
 SUBDIRS = $(compat_dir)
 
-bin_PROGRAMS = mbsync mdconvert
-
 mbsync_SOURCES = main.c sync.c config.c util.c socket.c driver.c drv_imap.c drv_maildir.c
-mbsync_LDADD = -ldb $(SSL_LIBS) $(SOCK_LIBS) $(SASL_LIBS) $(Z_LIBS)
+mbsync_LDADD = $(DB_LIBS) $(SSL_LIBS) $(SOCK_LIBS) $(SASL_LIBS) $(Z_LIBS)
 noinst_HEADERS = common.h config.h driver.h sync.h socket.h
 
 mdconvert_SOURCES = mdconvert.c
-mdconvert_LDADD = -ldb
+mdconvert_LDADD = $(DB_LIBS)
+if with_mdconvert
+mdconvert_prog = mdconvert
+mdconvert_man = mdconvert.1
+endif
 
 EXTRA_PROGRAMS = tst_timers
 
 tst_timers_SOURCES = tst_timers.c util.c
 
-man_MANS = mbsync.1 mdconvert.1
+bin_PROGRAMS = mbsync $(mdconvert_prog)
+man_MANS = mbsync.1 $(mdconvert_man)
 
 exampledir = $(docdir)/examples
 example_DATA = mbsyncrc.sample

src/compat/Makefile.am

@@ -1,7 +1,7 @@
 bin_PROGRAMS = isync
 
 isync_SOURCES = main.c config.c convert.c util.c
-isync_LDADD = -ldb
+isync_LDADD = $(DB_LIBS)
 noinst_HEADERS = isync.h
 
 man_MANS = isync.1

src/drv_maildir.c

@@ -38,7 +38,6 @@
 #include <time.h>
 #include <utime.h>
 
-#define USE_DB 1
 #ifdef __linux__
 # define LEGACY_FLOCK 1
 #endif