diff --git a/package/exim/exim.mk b/package/exim/exim.mk
index 3e8404b616..bfb138e9f8 100644
--- a/package/exim/exim.mk
+++ b/package/exim/exim.mk
@@ -11,15 +11,42 @@ EXIM_LICENSE = GPLv2+
 EXIM_LICENSE_FILES = LICENCE
 EXIM_DEPENDENCIES = pcre berkeleydb
 
-# These echos seem to be the sanest way to feed CC and CFLAGS to exim
+# 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_CONFIGURE_CMDS
-	$(INSTALL) -m 0644 -D package/exim/Local-Makefile $(@D)/Local/Makefile
-	echo "CC=$(TARGET_CC)" >>$(@D)/Local/Makefile
-	echo "CFLAGS=$(TARGET_CFLAGS)" >>$(@D)/Local/Makefile
-	echo "AR=$(TARGET_AR) cq" >>$(@D)/Local/Makefile
-	echo "RANLIB=$(TARGET_RANLIB)" >>$(@D)/Local/Makefile
-	echo "HOSTCC=$(HOSTCC)" >>$(@D)/Local/Makefile
-	echo "HOSTCFLAGS=$(HOSTCFLAGS)" >>$(@D)/Local/Makefile
+	$(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)
+	$(call exim-config-add,CC,$(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))
 endef
 
 # "The -j (parallel) flag must not be used with make"