configure: print info about required gmime 2.4 or 2.6 versions

In case required gmime (2.4 or 2.6) version if not found print information
about both alternatives (and currently minimal 2.6 version that is needed).

diff --git a/configure b/configure
index 393f859be74b4885b62c2cc84dd64853d3ff5b74..ace465ba4ebfdee60a011ab7775501a01c76805a 100755 (executable)
--- a/configure
+++ b/configure
@@ -48,8 +48,13 @@ WITH_EMACS=1
 WITH_BASH=1
 WITH_ZSH=1
 
-GMIME_24_VERSION='gmime-2.4'
-GMIME_26_VERSION='gmime-2.6 >= 2.6.7'
+# Compatible GMime versions (with constraints).
+# If using GMime 2.6, we need to have a version >= 2.6.5 to avoid a
+# crypto bug. We need 2.6.7 for permissive "From " header handling.
+GMIME_24_VERSION_CTR=''
+GMIME_24_VERSION="gmime-2.4 $GMIME_24_VERSION_CTR"
+GMIME_26_VERSION_CTR='>= 2.6.7'
+GMIME_26_VERSION="gmime-2.6 $GMIME_26_VERSION_CTR"
 
 WITH_GMIME_VERSIONS="$GMIME_26_VERSION;$GMIME_24_VERSION"
 
@@ -259,8 +264,6 @@ if [ ${have_xapian} = "0" ]; then
     errors=$((errors + 1))
 fi
 
-# If using GMime 2.6, we need to have a version >= 2.6.5 to avoid a
-# crypto bug. We need 2.6.7 for permissive "From " header handling.
 printf "Checking for GMime development files... "
 have_gmime=0
 IFS=';'
@@ -402,7 +405,8 @@ EOF
        echo "  http://xapian.org/"
     fi
     if [ $have_gmime -eq 0 ]; then
-       echo "  GMime 2.4 library (including development files such as headers)"
+       echo "  Either GMime 2.4 library" $GMIME_24_VERSION_CTR "or GMime 2.6 library" $GMIME_26_VERSION_CTR
+       echo "  (including development files such as headers)"
        echo "  http://spruce.sourceforge.net/gmime/"
        echo
     fi