[PATCH 2/2] travis.yml: Add missing 'flex' package to 'GCC (user)' job

[Vaibhav Jain]

Since commit fd8171fe52b5e("target/hexagon: import lexer for idef-parser") the
hexagon target uses 'flex' to generate idef-parser. However 'focal' may not have
'flex' pre-installed, consequently following error is seen with travis when
trying to execute the 'GCC (user)' job that also tries to build hexagon user
binary:

<snip>
export CONFIG="--disable-containers --disable-system"
<snip>
 Program flex found: NO

../target/hexagon/meson.build:179:4: ERROR: Program 'flex' not found or not
executable
<snip>

Fix this by explicitly add 'flex' to the list of addon apt-packages for the
'GCC (user)' job.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
 .travis.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.travis.yml b/.travis.yml
index 11894eb810..8dc71c294d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -237,6 +237,7 @@ jobs:
           - libglib2.0-dev
           - libgnutls28-dev
           - ninja-build
+          - flex
       env:
         - CONFIG="--disable-containers --disable-system"
 
-- 
2.39.2