travis: install libgnutls28-dev only for --with-gnutls build

Reduces the time needed for the other jobs a little.

Closes https://github.com/curl/curl/pull/3721

diff --git a/.travis.yml b/.travis.yml
index 4deceee6680f5d5bde8f5180ca9dc9c1acf81d22..441b63f22a323c067437bc1fc230a6d1ef587fcd 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -32,7 +32,6 @@ addons:
             - autopoint  # for libpsl that needs autoreconf that uses gettext that needs it
             - libunistring-dev # for libidn2 needed by libpsl
             - gnutls-bin
-            - libgnutls28-dev
 
 matrix:
     include:
@@ -161,6 +160,7 @@ matrix:
                   packages:
                       - *common_packages
                       - clang-7
+                      - libgnutls28-dev
         - os: linux
           compiler: clang
           dist: trusty