ci: Build both static and shared

This allows us to validate the objcopy trick in CI. It's basically free
to build both static and shared libraries anyway.

We only enable this for GCC builds right now, as Meson currently lacks
support for prelinking with other compilers.

.builds/alpine.yml

@@ -19,7 +19,7 @@ sources:
 tasks:
   - setup: |
       cd wlroots
-      meson build -Dauto_features=enabled -Dlibseat=disabled -Dxcb-errors=disabled
+      meson build --default-library=both -Dauto_features=enabled -Dlibseat=disabled -Dxcb-errors=disabled
   - build: |
       cd wlroots
       ninja -C build

.builds/archlinux.yml

@@ -20,7 +20,7 @@ sources:
 tasks:
   - setup: |
       cd wlroots
-      CC=gcc meson build-gcc -Dauto_features=enabled --prefix /usr
+      CC=gcc meson build-gcc --default-library=both -Dauto_features=enabled --prefix /usr
       CC=clang meson build-clang -Dauto_features=enabled
   - gcc: |
       cd wlroots/build-gcc