configure: Report an error when encountering invalid settings.

diff --git a/configure.ac b/configure.ac
index ac281225e0a703cb0478aa4a809f358bcf3360ff..c0a25c1dc9110a14025a37bb350bc0f19807b07a 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -254,11 +254,15 @@ AC_ARG_WITH([libdbi],
                [AS_HELP_STRING([--with-libdbi], [libdbi support (default: auto)])],
                [with_libdbi="$withval"],
                [with_libdbi="yes"])
-if test "x$with_libdbi" = "xyes"; then
+if test "x$with_libdbi" = "xyes" || test "x$with_libdbi" = "xauto"; then
        AC_CHECK_HEADERS([dbi/dbi.h],
                        [with_libdbi="yes"],
                        [with_libdbi="no (dbi/dbi.h not found)"])
-fi
+else if test "x$with_libdbi" = "xno"; then
+       with_libdbi="$with_libdbi (disabled on command-line)"
+else
+       AC_MSG_ERROR([Invalid value for option --with-libdbi=$with_libdbi (expected "yes", "no", or "auto")])
+fi; fi
 if test "x$with_libdbi" = "xyes"; then
        AC_CHECK_LIB([dbi], [dbi_initialize],
                        [with_libdbi="yes"],
@@ -287,7 +291,12 @@ AC_ARG_WITH([readline],
 
 if test "x$readline_support" = "xyes"; then
        readline_support="auto"
-fi
+else if test "x$readline_support" != "xauto" \
+               && test "x$readline_support" != "xno" \
+               && test "x$readline_support" != "xlibedit" \
+               && test "x$readline_support" != "xlibreadline"; then
+       AC_MSG_ERROR([Invalid value for option --with-readline=$readline_support (expected "yes", "no", "auto", "libedit", or "libreadline")])
+fi; fi
 
 have_libedit="no"
 if test "x$readline_support" = "xauto" \