travis: Add Travis CI config file

There is a really convenient service for open source project from Travis
CI: They allow for free CI testing using their infrastructure.

GRUB has had issues with broken builds for various targets for a long time
already. The main reason is a lack of CI to just do smoke tests on whether
all targets still at least compile.

This patch adds a Travis config file which builds (almost) all currently
available targets.

On top of that, this Travis config also runs a small execution test on the
x86_64-efi target.

All of this config file can easily be extended further on. It probably
makes sense to do something similar to the u-boot test infrastructure
that communicates with the payload properly. Going forward, we also will
want to do more QEMU runtime checks for other targets.

Currently, with this config alone, I already see about half of the available
targets as broken. So it's definitely desperately needed :).

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

.travis.yml

@@ -0,0 +1,108 @@
+# SPDX-License-Identifier: GPL-3.0+
+# Originally Copyright Roger Meier <r.meier@siemens.com>
+# Adapted for GRUB by Alexander Graf <agraf@suse.de>
+#
+# Build GRUB on Travis CI - https://www.travis-ci.org/
+#
+
+dist: xenial
+
+language: c
+
+addons:
+  apt:
+    packages:
+    - libsdl1.2-dev
+    - lzop
+    - ovmf
+    - python
+    - qemu-system
+    - unifont
+
+env:
+  global:
+    # Include all cross toolchain paths, so we can just call them later down.
+    - PATH=/tmp/qemu-install/bin:/tmp/grub/bin:/usr/bin:/bin:/tmp/cross/gcc-8.1.0-nolibc/aarch64-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/arm-linux-gnueabi/bin:/tmp/cross/gcc-8.1.0-nolibc/ia64-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/mips64-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/powerpc64-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/riscv32-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/riscv64-linux/bin:/tmp/cross/gcc-8.1.0-nolibc/sparc64-linux/bin
+
+before_script:
+  # Install necessary toolchains based on $CROSS_TARGETS variable.
+  - mkdir /tmp/cross
+  # These give us binaries like /tmp/cross/gcc-8.1.0-nolibc/ia64-linux/bin/ia64-linux-gcc
+  - for i in $CROSS_TARGETS; do
+        ( cd /tmp/cross; wget -t 3 -O - https://mirrors.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/x86_64-gcc-8.1.0-nolibc-$i.tar.xz | tar xJ );
+    done
+
+script:
+  # Comments must be outside the command strings below, or the Travis parser
+  # will get confused.
+  - ./autogen.sh
+
+  # Build all selected GRUB targets.
+  - for target in $GRUB_TARGETS; do
+      plat=${target#*-};
+      arch=${target%-*};
+      [ "$arch" = "arm64" ] && arch=aarch64-linux;
+      [ "$arch" = "arm" ] && arch=arm-linux-gnueabi;
+      [ "$arch" = "ia64" ] && arch=ia64-linux;
+      [ "$arch" = "mipsel" ] && arch=mips64-linux;
+      [ "$arch" = "powerpc" ] && arch=powerpc64-linux;
+      [ "$arch" = "riscv32" ] && arch=riscv32-linux;
+      [ "$arch" = "riscv64" ] && arch=riscv64-linux;
+      [ "$arch" = "sparc64" ] && arch=sparc64-linux;
+      echo "Building $target";
+      mkdir obj-$target;
+      JOBS=`getconf _NPROCESSORS_ONLN 2> /dev/null || echo 1`;
+      [ "$JOBS" == 1 ] || JOBS=$(($JOBS + 1));
+      ( cd obj-$target && ../configure --target=$arch --with-platform=$plat --prefix=/tmp/grub && make -j$JOBS && make -j$JOBS install ) &> log || ( cat log; false );
+    done
+
+  # Our test canary.
+  - echo -e "insmod echo\\ninsmod reboot\\necho hello world\\nreboot" > grub.cfg
+
+  # Assemble images and possibly run them.
+  - for target in $GRUB_TARGETS; do grub-mkimage -c grub.cfg -p / -O $target -o grub-$target echo reboot normal; done
+
+  # Run images we know how to run.
+  - if [[ "$GRUB_TARGETS" == *"x86_64-efi"* ]]; then qemu-system-x86_64 -bios /usr/share/ovmf/OVMF.fd -m 512 -no-reboot -nographic -net nic -net user,tftp=.,bootfile=grub-x86_64-efi | tee grub.log && grep "hello world" grub.log; fi
+
+matrix:
+  include:
+  # Each env setting here is a dedicated build.
+    - name: "x86_64"
+      env:
+        - GRUB_TARGETS="x86_64-efi x86_64-xen"
+    - name: "i386"
+      env:
+        - GRUB_TARGETS="i386-coreboot i386-efi i386-ieee1275 i386-multiboot i386-pc i386-qemu i386-xen i386-xen_pvh"
+    - name: "powerpc"
+      env:
+        - GRUB_TARGETS="powerpc-ieee1275"
+        - CROSS_TARGETS="powerpc64-linux"
+    - name: "sparc64"
+      env:
+        - GRUB_TARGETS="sparc64-ieee1275"
+        - CROSS_TARGETS="sparc64-linux"
+    - name: "ia64"
+      env:
+        - GRUB_TARGETS="ia64-efi"
+        - CROSS_TARGETS="ia64-linux"
+    - name: "mips"
+      env:
+        - GRUB_TARGETS="mips-arc mipsel-arc mipsel-qemu_mips mips-qemu_mips"
+        - CROSS_TARGETS="mips64-linux"
+    - name: "arm"
+      env:
+        - GRUB_TARGETS="arm-coreboot arm-efi arm-uboot"
+        - CROSS_TARGETS="arm-linux-gnueabi"
+    - name: "arm64"
+      env:
+        - GRUB_TARGETS="arm64-efi"
+        - CROSS_TARGETS="aarch64-linux"
+    - name: "riscv32"
+      env:
+        - GRUB_TARGETS="riscv32-efi"
+        - CROSS_TARGETS="riscv32-linux"
+    - name: "riscv64"
+      env:
+        - GRUB_TARGETS="riscv64-efi"
+        - CROSS_TARGETS="riscv64-linux"