gitlab-ci: Build i386 and ARM drivers in surfaceless mode.

I don't particularly care about getting x86/ARM cross-build coverage
of all the window systems, but we do want to be building src/mesa/
(for x86 asm) and gallium drivers (for vc4 NEON asm).  I'm also hoping
to use these build products for testing freedreno on actual HW (which
we do using surfaceless).

This increases the docker image from 1.4G to 1.5G.

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>

.gitlab-ci/debian-install.sh

@@ -5,6 +5,11 @@ set -o xtrace
 
 export DEBIAN_FRONTEND=noninteractive
 
+CROSS_ARCHITECTURES="armhf arm64 i386"
+for arch in $CROSS_ARCHITECTURES; do
+    dpkg --add-architecture $arch
+done
+
 apt-get install -y \
       apt-transport-https \
       ca-certificates \
@@ -75,6 +80,22 @@ apt-get install -y \
       gettext \
       make
 
+# Cross-build Mesa deps
+for arch in $CROSS_ARCHITECTURES; do
+    apt-get install -y \
+            libdrm-dev:${arch} \
+            libexpat1-dev:${arch} \
+            libelf-dev:${arch}
+done
+apt-get install -y \
+        dpkg-dev \
+        gcc-aarch64-linux-gnu \
+        g++-aarch64-linux-gnu \
+        gcc-arm-linux-gnueabihf \
+        g++-arm-linux-gnueabihf \
+        gcc-i686-linux-gnu \
+        g++-i686-linux-gnu
+
 # for 64bit windows cross-builds
 apt-get install -y mingw-w64
 
@@ -185,7 +206,6 @@ apt-get install -y libxml2-utils
 apt-get purge -y \
       automake \
       libtool \
-      make \
       curl \
       unzip \
       wget \

.gitlab-ci/meson-build.sh

@@ -16,6 +16,7 @@ fi
 
 rm -rf _build
 meson _build --native-file=native.file \
+      ${CROSS} \
       -D buildtype=debug \
       -D build-tests=true \
       -D libunwind=${UNWIND} \