[glib] ci: Install Meson from PyPI

[Emmanuele Bassi <ebassi src gnome org>]

commit 19ffd365ff7b75e406242070512d50c8f5c2766c
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Mar 29 09:57:55 2018 +0100

    ci: Install Meson from PyPI
    
    The base Fedora image we use for our CI does not always have an updated
    Meson package to fit our requirements. Let's install Meson using
    Python's pip instead.

 .gitlab-ci/Dockerfile | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/.gitlab-ci/Dockerfile b/.gitlab-ci/Dockerfile
index 69434ca09..1089d0cdf 100644
--- a/.gitlab-ci/Dockerfile
+++ b/.gitlab-ci/Dockerfile
@@ -16,10 +16,16 @@ RUN dnf -y install \
     libmount-devel \
     libselinux-devel \
     libxslt \
-    meson \
+    ninja-build \
     pcre-devel \
+    python3 \
+    python3-pip \
+    python3-wheel \
     systemtap-sdt-devel \
-    zlib-devel
+    zlib-devel \
+ && dnf clean all
+
+RUN pip3 install meson
 
 ARG HOST_USER_ID=5555
 ENV HOST_USER_ID ${HOST_USER_ID}
@@ -28,4 +34,4 @@ RUN useradd -u $HOST_USER_ID -ms /bin/bash user
 USER user
 WORKDIR /home/user
 
-ENV LANG C.utf8
+ENV LANG C.UTF-8