Add --disable-dynamic/--disable-preload and update docs

Options were in README but removed at some point.  They
are useful so add them back.

Document BACKENDS and PRELOADABLE_BACKENDS variables in
README as well as in configure --help output.

ChangeLog

@@ -4,6 +4,14 @@
 	If it needs to have two behaviors then we need to
 	create two libraries.  Now preloading is working in
 	libsane.so again and disabled in libsane-dll.so.
+	* configure.in, configure, README, */Makefile.*:
+	Update README to describe use of BACKENDS and
+	PRELOADABLE_BACKENDS to limit backend compiles.
+	Also, mark those in configure.in as variables so
+	they show up in "configure --help".
+	Add back the useful --disable-dynamic and
+	--disable-preload that appear to have been removed
+	at some point but are documented in README.
 
 2011-11-07 Chris Bagwell <chris at cnpbagwell dot com>
 	* ltmain.sh: Disable sane's soname libtool hack for

Makefile.in

@@ -138,6 +138,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

README

@@ -45,7 +45,7 @@ libraries and their respective header files are available before running
 configure. On some Linux distributions the header files are part of separate
 packages (e.g. usb.h in libusb-devel or libusb-dev). These must also be
 installed.
-        
+
         - libusb (>=0.1.8): Strongly recommended if you use a USB scanner.
           Some backends won't work without libusb at all.
 
@@ -87,18 +87,19 @@ configure options, there are the following SANE specific options:
 	Disable dynamic loading of backends (in the dll backend).
 	configure normally turns on dynamic loading when it
 	can find the appropriate header files and libraries
-	(<dlfcn.h> and -dl).
+	(<dlfcn.h> and -ldl).
 
  --enable-static
         Use static libraries (turned off by default).
 
  --enable-preload
         Preload backends into DLL backend.  This is useful for debugging,
-	when dynamic loading is unavailable, or to reduce runtime linking
-	overheads.  If dynamic loading or shared libraries are unavailable
-	or disabled, this option is turned on automatically.
-	
- --enable-scsibuffersize=N 
+	when dynamic loading is unavailable, to reduce runtime linking
+	overheads, or when you only want to distribute a single DLL with
+	all backends available.  If dynamic loading or shared libraries are
+	unavailable or disabled, this option is turned on automatically.
+
+ --enable-scsibuffersize=N
         Specify the buffer size of the buffer for SCSI commands. The default
 	value is 131072 bytes (128 kb). This may be changed at runtime by
 	setting	the environment variable SANE_SG_BUFFERSIZE to the desired
@@ -118,11 +119,23 @@ configure options, there are the following SANE specific options:
 	Means, that some backends will use a lockfile for allowing multiple
 	access to one scanner. This is useful, i.e. one frontend is scanning
 	the button status and another one will scan. The path to the lock
-	files is define by --localstatedir at the configure step and is 
+	files is define by --localstatedir at the configure step and is
 	$localstatedir/lock/sane. The default group is uucp and can be
 	changed by using --with-group=newgroup. If you do not want any
 	backend to use a lockfile, simply use --disable-locking.
 
+To limit the backends that are compiled, set the variable BACKENDS to
+the list of backends to compile.  The following will limit compiling
+to the epson2 and fujitsu backends:
+
+  ./configure BACKENDS="epson2 fujitsu"
+
+To limit the backends that are preloaded into the DLL, set the variable
+PRELOADABLE_BACKENDS.  The following will limit compiling  to the epson2
+and fujitsu backends but only preloads the epson2 backend:
+
+  ./configure BACKENDS="epson2 futjisu" PRELOADABLE_BACKENDS="epson2"
+
 In addition to these configuration options, there are some more SANE-specific
 options and many standard-options.  To get a description of available options,
 invoke configure with option --help.

backend/Makefile.in

@@ -1501,6 +1501,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

configure

@@ -628,6 +628,7 @@ BACKEND_LIBS_ENABLED
 SANEI_SANEI_JPEG_LO
 HAVE_JPEG_FALSE
 HAVE_JPEG_TRUE
+BACKENDS
 COMPILE_SANED_FALSE
 COMPILE_SANED_TRUE
 configdir
@@ -809,6 +810,8 @@ enable_libusb
 enable_scsibuffersize
 enable_scsi_directio
 enable_ipv6
+enable_dynamic
+enable_preload
 enable_static
 enable_shared
 with_pic
@@ -840,7 +843,9 @@ LIBV4L_LIBS
 AVAHI_CFLAGS
 AVAHI_LIBS
 LIBUSB_1_0_CFLAGS
-LIBUSB_1_0_LIBS'
+LIBUSB_1_0_LIBS
+BACKENDS
+PRELOADABLE_BACKENDS'
 
 
 # Initialize some variables set by options.
@@ -1480,6 +1485,8 @@ Optional Features:
   --enable-scsi-directio  enable SCSI direct IO (Linux only, dangerous, see
                           README.linux)
   --disable-ipv6          disable IPv6 support
+  --disable-dynamic       Disable dynamic loading of backends
+  --disable-preload       Disable preloading of backends
   --enable-static[=PKGS]  build static libraries [default=no]
   --enable-shared[=PKGS]  build shared libraries [default=yes]
   --enable-fast-install[=PKGS]
@@ -1534,6 +1541,9 @@ Some influential environment variables:
               C compiler flags for LIBUSB_1_0, overriding pkg-config
   LIBUSB_1_0_LIBS
               linker flags for LIBUSB_1_0, overriding pkg-config
+  BACKENDS    list of backends to compile
+  PRELOADABLE_BACKENDS
+              list of backends to preload into single DLL
 
 Use these variables to override the choices made by `configure' or to help
 it to find libraries and programs with nonstandard names/locations.
@@ -10140,6 +10150,21 @@ else
   ipv6="no"
 fi
 
+# Check whether --enable-dynamic was given.
+if test "${enable_dynamic+set}" = set; then :
+  enableval=$enable_dynamic; enable_dynamic=$enableval
+else
+  enable_dynamic=yes
+fi
+
+# Check whether --enable-preload was given.
+if test "${enable_preload+set}" = set; then :
+  enableval=$enable_preload; enable_preload=$enableval
+else
+  enable_preload=auto
+fi
+
+
 enable_win32_dll=yes
 
 case $host in
@@ -17566,6 +17591,7 @@ ALL_BACKENDS="abaton agfafocus apple artec artec_eplus48u as6e \
 # are in automatic mode then remove backend from list instead.
 user_selected_backends="yes"
 
+
 if eval "test x$enable_local_backends = xno"; then
    BACKENDS="net"
 else
@@ -17713,10 +17739,13 @@ for backend in ${BACKENDS} ; do
 done
 
 
-if test "${enable_shared}" = "no"; then
-  enable_preload=yes
+
+if test "${enable_preload}" = "auto"; then
+  if test "${enable_shared}" = "no" || test "${enable_dynamic}" != "yes"; then
+    enable_preload=yes
+  fi
 fi
-if test "${enable_dynamic}" != yes || test "${enable_preload}" = "yes"; then
+if test "${enable_preload}" = "yes"; then
   echo "preloading backends into DLL"
 
   # If user specifies backends manually then cause configure
@@ -17731,7 +17760,7 @@ if test "${enable_dynamic}" != yes || test "${enable_preload}" = "yes"; then
       { $as_echo "$as_me:${as_lineno-$LINENO}: Manually selected preloadable backends: ${PRELOADABLE_BACKENDS}" >&5
 $as_echo "$as_me: Manually selected preloadable backends: ${PRELOADABLE_BACKENDS}" >&6;}
     else
-      PRELOADABLE_BACKENDS="$ALL_BACKENDS"
+      PRELOADABLE_BACKENDS="$BACKENDS"
       user_selected_backends="no"
     fi
   fi

configure.in

@@ -508,6 +508,15 @@ fi
 dnl ***********************************************************************
 dnl initialize libtool
 dnl ***********************************************************************
+AC_ARG_ENABLE(dynamic,
+	AC_HELP_STRING([--disable-dynamic],
+		       [Disable dynamic loading of backends]),
+	[enable_dynamic=$enableval], [enable_dynamic=yes])
+AC_ARG_ENABLE(preload,
+	AC_HELP_STRING([--disable-preload],
+		       [Disable preloading of backends]),
+	[enable_preload=$enableval], [enable_preload=auto])
+
 AC_LIBTOOL_WIN32_DLL
 AC_DISABLE_STATIC
 AC_PROG_LIBTOOL
@@ -571,6 +580,7 @@ ALL_BACKENDS="abaton agfafocus apple artec artec_eplus48u as6e \
 # are in automatic mode then remove backend from list instead.
 user_selected_backends="yes"
 
+AC_ARG_VAR(BACKENDS, [list of backends to compile])
 if eval "test x$enable_local_backends = xno"; then 
    BACKENDS="net"
 else
@@ -607,10 +617,13 @@ for backend in ${BACKENDS} ; do
 done
 AC_SUBST(BACKEND_LIBS_ENABLED)
 
-if test "${enable_shared}" = "no"; then
-  enable_preload=yes
+AC_ARG_VAR(PRELOADABLE_BACKENDS, [list of backends to preload into single DLL])
+if test "${enable_preload}" = "auto"; then
+  if test "${enable_shared}" = "no" || test "${enable_dynamic}" != "yes"; then
+    enable_preload=yes
+  fi
 fi
-if test "${enable_dynamic}" != yes || test "${enable_preload}" = "yes"; then
+if test "${enable_preload}" = "yes"; then
   echo "preloading backends into DLL"
 
   # If user specifies backends manually then cause configure
@@ -624,7 +637,7 @@ if test "${enable_dynamic}" != yes || test "${enable_preload}" = "yes"; then
     if test "${PRELOADABLE_BACKENDS}" != "" ; then
       AC_MSG_NOTICE([Manually selected preloadable backends: ${PRELOADABLE_BACKENDS}])
     else
-      PRELOADABLE_BACKENDS="$ALL_BACKENDS"
+      PRELOADABLE_BACKENDS="$BACKENDS"
       user_selected_backends="no"
     fi
   fi

doc/Makefile.in

@@ -92,6 +92,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 

frontend/Makefile.in

@@ -100,6 +100,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

include/Makefile.in

@@ -86,6 +86,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

japi/Makefile.in

@@ -109,6 +109,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

lib/Makefile.in

@@ -85,6 +85,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

po/Makefile.in

@@ -62,6 +62,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

sanei/Makefile.in

@@ -100,6 +100,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

testsuite/Makefile.in

@@ -59,6 +59,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@

tools/Makefile.in

@@ -119,6 +119,7 @@ AUTOMAKE = @AUTOMAKE@
 AVAHI_CFLAGS = @AVAHI_CFLAGS@
 AVAHI_LIBS = @AVAHI_LIBS@
 AWK = @AWK@
+BACKENDS = @BACKENDS@
 BACKEND_CONFS_ENABLED = @BACKEND_CONFS_ENABLED@
 BACKEND_LIBS_ENABLED = @BACKEND_LIBS_ENABLED@
 BACKEND_MANS_ENABLED = @BACKEND_MANS_ENABLED@