configure: add help note about gmime version

diff --git a/configure b/configure
index 71981b7c614a58f6b916acd49cf6515253dce396..5602be247611558fdb1cc1f743e0ac3cf9239a82 100755 (executable)
--- a/configure
+++ b/configure
@@ -114,6 +114,10 @@ Fine tuning of some installation directories is available:
        --bashcompletiondir=DIR Bash completions files [SYSCONFDIR/bash_completion.d]
        --zshcompletiondir=DIR  Zsh completions files [PREFIX/share/zsh/functions/Completion/Unix]
 
+Some specific library versions can be specified (auto-detected otherwise):
+
+        --with-gmime-version=VERS       Specify GMIME version (2.4 or 2.6)
+
 Some features can be disabled (--with-feature=no is equivalent to
 --without-feature) :