################################################################################
  #
  # exim
  #
  ################################################################################
  
  EXIM_VERSION = 4.87
  EXIM_SOURCE = exim-$(EXIM_VERSION).tar.bz2
  EXIM_SITE = ftp://ftp.exim.org/pub/exim/exim4
  EXIM_LICENSE = GPLv2+
  EXIM_LICENSE_FILES = LICENCE
  EXIM_DEPENDENCIES = pcre berkeleydb host-pkgconf
  
  # Modify a variable value. It must already exist in the file, either
  # commented or not.
  define exim-config-change # variable-name, variable-value
  	$(SED) 's,^[#[:space:]]*$1[[:space:]]*=.*$$,$1=$2,' \
  		$(@D)/Local/Makefile
  endef
  
  # Comment-out a variable. Has no effect if it does not exits.
  define exim-config-unset # variable-name
  	$(SED) 's,^\([[:space:]]*$1[[:space:]]*=.*$$\),# \1,' \
  		$(@D)/Local/Makefile
  endef
  
  # Add a variable definition. It must not already exist in the file,
  # otherwise it would be defined twice with potentially different values.
  define exim-config-add # variable-name, variable-value
  	echo "$1=$2" >>$(@D)/Local/Makefile
  endef
  
  define EXIM_USE_CUSTOM_CONFIG_FILE
  	$(INSTALL) -m 0644 $(BR2_PACKAGE_EXIM_CUSTOM_CONFIG_FILE) \
  		$(@D)/Local/Makefile
  endef
  
  define EXIM_USE_DEFAULT_CONFIG_FILE
  	$(INSTALL) -m 0644 $(@D)/src/EDITME $(@D)/Local/Makefile
  	$(call exim-config-change,BIN_DIRECTORY,/usr/sbin)
  	$(call exim-config-change,CONFIGURE_FILE,/etc/exim/configure)
  	$(call exim-config-change,EXIM_USER,ref:exim)
  	$(call exim-config-change,EXIM_GROUP,mail)
  	$(call exim-config-change,TRANSPORT_LMTP,yes)
  	$(call exim-config-change,PCRE_LIBS,-lpcre)
  	$(call exim-config-change,PCRE_CONFIG,no)
  	$(call exim-config-change,HAVE_ICONV,no)
  	$(call exim-config-unset,EXIM_MONITOR)
  	$(call exim-config-change,AUTH_PLAINTEXT,yes)
  	$(call exim-config-change,AUTH_CRAM_MD5,yes)
  endef
  
  ifeq ($(BR2_PACKAGE_DOVECOT),y)
  EXIM_DEPENDENCIES += dovecot
  define EXIM_USE_DEFAULT_CONFIG_FILE_DOVECOT
  	$(call exim-config-change,AUTH_DOVECOT,yes)
  endef
  endif
  
  ifeq ($(BR2_PACKAGE_CLAMAV),y)
  EXIM_DEPENDENCIES += clamav
  define EXIM_USE_DEFAULT_CONFIG_FILE_CLAMAV
  	$(call exim-config-change,WITH_CONTENT_SCAN,yes)
  endef
  endif
  
  ifeq ($(BR2_PACKAGE_OPENSSL),y)
  EXIM_DEPENDENCIES += openssl
  define EXIM_USE_DEFAULT_CONFIG_FILE_OPENSSL
  	$(call exim-config-change,SUPPORT_TLS,yes)
  	$(call exim-config-change,USE_OPENSSL_PC,openssl)
  endef
  endif
  
  # only glibc provides libnsl, remove -lnsl for all other toolchains
  # http://bugs.exim.org/show_bug.cgi?id=1564
  ifeq ($(BR2_TOOLCHAIN_USES_GLIBC),)
  define EXIM_REMOVE_LIBNSL_FROM_MAKEFILE
  	$(SED) 's/-lnsl//g' $(@D)/OS/Makefile-Linux
  endef
  endif
  
  # musl does not provide struct ip_options nor struct ip_opts (but it is
  # available with both glibc and uClibc)
  ifeq ($(BR2_TOOLCHAIN_USES_MUSL),y)
  define EXIM_FIX_IP_OPTIONS_FOR_MUSL
  	$(SED) 's/#define GLIBC_IP_OPTIONS/#define DARWIN_IP_OPTIONS/' \
  		$(@D)/OS/os.h-Linux
  endef
  endif
  
  define EXIM_CONFIGURE_TOOLCHAIN
  	$(call exim-config-add,CC,$(TARGET_CC))
  	$(call exim-config-add,CFLAGS,$(TARGET_CFLAGS))
  	$(call exim-config-add,AR,$(TARGET_AR) cq)
  	$(call exim-config-add,RANLIB,$(TARGET_RANLIB))
  	$(call exim-config-add,HOSTCC,$(HOSTCC))
  	$(call exim-config-add,HOSTCFLAGS,$(HOSTCFLAGS))
  	$(EXIM_REMOVE_LIBNSL_FROM_MAKEFILE)
  	$(EXIM_FIX_IP_OPTIONS_FOR_MUSL)
  endef
  
  ifneq ($(call qstrip,$(BR2_PACKAGE_EXIM_CUSTOM_CONFIG_FILE)),)
  define EXIM_CONFIGURE_CMDS
  	$(EXIM_USE_CUSTOM_CONFIG_FILE)
  	$(EXIM_CONFIGURE_TOOLCHAIN)
  endef
  else # CUSTOM_CONFIG
  define EXIM_CONFIGURE_CMDS
  	$(EXIM_USE_DEFAULT_CONFIG_FILE)
  	$(EXIM_USE_DEFAULT_CONFIG_FILE_DOVECOT)
  	$(EXIM_USE_DEFAULT_CONFIG_FILE_CLAMAV)
  	$(EXIM_USE_DEFAULT_CONFIG_FILE_OPENSSL)
  	$(EXIM_CONFIGURE_TOOLCHAIN)
  endef
  endif # CUSTOM_CONFIG
  
  # exim needs a bit of love to build statically
  ifeq ($(BR2_STATIC_LIBS),y)
  EXIM_STATIC_FLAGS = LFLAGS="-pthread --static"
  endif
  
  # "The -j (parallel) flag must not be used with make"
  # (http://www.exim.org/exim-html-current/doc/html/spec_html/ch04.html)
  define EXIM_BUILD_CMDS
  	$(TARGET_MAKE_ENV) build=br $(MAKE1) -C $(@D) $(EXIM_STATIC_FLAGS)
  endef
  
  # Need to replicate the LFLAGS in install, as exim still wants to build
  # something when installing...
  define EXIM_INSTALL_TARGET_CMDS
  	DESTDIR=$(TARGET_DIR) INSTALL_ARG="-no_chown -no_symlink" build=br \
  	  $(MAKE1) -C $(@D) $(EXIM_STATIC_FLAGS) install
  	chmod u+s $(TARGET_DIR)/usr/sbin/exim
  endef
  
  define EXIM_USERS
  	exim 88 mail 8 * - - - exim
  endef
  
  define EXIM_INSTALL_INIT_SYSV
  	$(INSTALL) -D -m 755 package/exim/S86exim \
  		$(TARGET_DIR)/etc/init.d/S86exim
  endef
  
  define EXIM_INSTALL_INIT_SYSTEMD
  	$(INSTALL) -D -m 644 package/exim/exim.service \
  		$(TARGET_DIR)/usr/lib/systemd/system/exim.service
  	mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
  	ln -sf ../../../../usr/lib/systemd/system/exim.service \
  		$(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/exim.service
  endef
  
  $(eval $(generic-package))