Suggest --disable-doh when libnghttp2 is not found

Extend the error message displayed when support for DNS over HTTPS is
requested but libnghttp2 is unavailable at build time, in order to help
the user find a way out of such a situation.

diff --git a/configure.ac b/configure.ac
index 311778a4416f2164821d95e0bfdfbf8b24f61a94..48415e5638daf7e974fd748416ba59d1f95e3b1b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -578,7 +578,8 @@ AS_IF([test "$enable_doh" = "yes"],
               [no],[AC_MSG_ERROR([Use '--disable-doh' to disable DNS-over-HTTPS support])],
               [auto|yes],[PKG_CHECK_MODULES([LIBNGHTTP2], [libnghttp2 >= 1.6.0],
                                             [AC_DEFINE([HAVE_LIBNGHTTP2], [1], [Build with DNS-over-HTTPS support])],
-                                            [AC_MSG_ERROR([DNS-over-HTTPS support requested, but libnghttp2 not found])])],
+                                            [AC_MSG_ERROR(m4_normalize([DNS-over-HTTPS support requested, but libnghttp2 not found.
+                                                                        Either install libnghttp2 or use --disable-doh.]))])],
               [AC_MSG_ERROR([Specifying libnghttp2 installation path is not supported, adjust PKG_CONFIG_PATH instead])])])
 
 AM_CONDITIONAL([HAVE_LIBNGHTTP2], [test -n "$LIBNGHTTP2_LIBS"])