ci: Update to zig 0.9.1

 .builds/alpine.yml             |  8 ++++----
 .builds/archlinux.yml          |  8 ++++----
 .builds/freebsd.yml            |  8 ++++----
 .github/workflows/ci_build.yml | 10 +++++-----
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/.builds/alpine.yml b/.builds/alpine.yml
index 8a90ce8..0963179 100644
--- a/.builds/alpine.yml
+++ b/.builds/alpine.yml
@@ -38,11 +38,11 @@ tasks:
       sudo ninja -C build/ install
       cd ..
 
-      wget https://ziglang.org/download/0.9.0/zig-linux-x86_64-0.9.0.tar.xz
+      wget https://ziglang.org/download/0.9.1/zig-linux-x86_64-0.9.1.tar.xz
       # Remove a lot of useless lines from tar output.
-      tar -xvf zig-linux-x86_64-0.9.0.tar.xz 1>/dev/null
-      sudo mv zig-linux-x86_64-0.9.0/zig /usr/bin/
-      sudo mv zig-linux-x86_64-0.9.0/lib /usr/lib/zig
+      tar -xvf zig-linux-x86_64-0.9.1.tar.xz 1>/dev/null
+      sudo mv zig-linux-x86_64-0.9.1/zig /usr/bin/
+      sudo mv zig-linux-x86_64-0.9.1/lib /usr/lib/zig
   - build: |
       cd river
       zig build
diff --git a/.builds/archlinux.yml b/.builds/archlinux.yml
index a01f17d..6f62449 100644
--- a/.builds/archlinux.yml
+++ b/.builds/archlinux.yml
@@ -35,11 +35,11 @@ tasks:
       sudo ninja -C build/ install
       cd ..
 
-      wget https://ziglang.org/download/0.9.0/zig-linux-x86_64-0.9.0.tar.xz
+      wget https://ziglang.org/download/0.9.1/zig-linux-x86_64-0.9.1.tar.xz
       # Remove a lot of useless lines from tar output.
-      tar -xvf zig-linux-x86_64-0.9.0.tar.xz 1>/dev/null
-      sudo mv zig-linux-x86_64-0.9.0/zig /usr/bin/
-      sudo mv zig-linux-x86_64-0.9.0/lib /usr/lib/zig
+      tar -xvf zig-linux-x86_64-0.9.1.tar.xz 1>/dev/null
+      sudo mv zig-linux-x86_64-0.9.1/zig /usr/bin/
+      sudo mv zig-linux-x86_64-0.9.1/lib /usr/lib/zig
   - build: |
       cd river
       zig build
diff --git a/.builds/freebsd.yml b/.builds/freebsd.yml
index 9f4a9d2..3f2674d 100644
--- a/.builds/freebsd.yml
+++ b/.builds/freebsd.yml
@@ -39,11 +39,11 @@ tasks:
       sudo ninja -C build/ install
       cd ..
 
-      wget https://ziglang.org/download/0.9.0/zig-freebsd-x86_64-0.9.0.tar.xz
+      wget https://ziglang.org/download/0.9.1/zig-freebsd-x86_64-0.9.1.tar.xz
       # Remove a lot of useless lines from tar output.
-      tar -xvf zig-freebsd-x86_64-0.9.0.tar.xz 1>/dev/null
-      sudo mv zig-freebsd-x86_64-0.9.0/zig /usr/bin/
-      sudo mv zig-freebsd-x86_64-0.9.0/lib /usr/lib/zig
+      tar -xvf zig-freebsd-x86_64-0.9.1.tar.xz 1>/dev/null
+      sudo mv zig-freebsd-x86_64-0.9.1/zig /usr/bin/
+      sudo mv zig-freebsd-x86_64-0.9.1/lib /usr/lib/zig
   - build: |
       cd river
       zig build
diff --git a/.github/workflows/ci_build.yml b/.github/workflows/ci_build.yml
index 94fe86e..64dc462 100644
--- a/.github/workflows/ci_build.yml
+++ b/.github/workflows/ci_build.yml
@@ -38,15 +38,15 @@ jobs:
 
           git clone https://gitlab.freedesktop.org/wlroots/wlroots.git
           cd wlroots
-          git checkout 0.15.0
+          git checkout 0.15.1
           meson build --auto-features=enabled -Drenderers=gles2 -Dexamples=false \
             -Dwerror=false -Db_ndebug=false --prefix /usr
           ninja -C build install
 
-          wget https://ziglang.org/download/0.9.0/zig-linux-x86_64-0.9.0.tar.xz
-          tar -xvf zig-linux-x86_64-0.9.0.tar.xz
-          mv zig-linux-x86_64-0.9.0/zig /usr/bin/
-          mv zig-linux-x86_64-0.9.0/lib /usr/lib/zig
+          wget https://ziglang.org/download/0.9.1/zig-linux-x86_64-0.9.1.tar.xz
+          tar -xvf zig-linux-x86_64-0.9.1.tar.xz
+          mv zig-linux-x86_64-0.9.1/zig /usr/bin/
+          mv zig-linux-x86_64-0.9.1/lib /usr/lib/zig
           zig env
 
       - name: checkout