gitlab-ci: Use GNU make on FreeBSD

The Makefile.am files contain % pattern rules that are not supported by
`make` (bmake) on FreeBSD. Since the replacing the patterns is non-trivial,
this commit updates the CI script to use GNU make when building on FreeBSD.

.gitlab-ci.yml

@@ -415,7 +415,7 @@ freebsd image:
     # ones starting with ci_ to ci-build.sh manually. This works because
     # $(env | grep "ci_.*=") is evaluated on the current host not in the VM.
     # We also have to forward builddir since this is required by ci-build.sh.
-    - /app/vmctl exec "cd $CI_PROJECT_NAME && env builddir=$builddir $(echo $(env | grep "ci_.*=")) bash -x ./tools/ci-build.sh $CI_BUILD_ARGS"
+    - /app/vmctl exec "cd $CI_PROJECT_NAME && env make=gmake builddir=$builddir $(echo $(env | grep "ci_.*=")) bash -x ./tools/ci-build.sh $CI_BUILD_ARGS"
     # Copy build artifacts from the VM for archiving/JUnit XML display
     - mkdir -p "$builddir"
     - scp -v "vm:$CI_PROJECT_NAME/$builddir/config.h" . || true

tools/ci-build.sh

@@ -260,7 +260,10 @@ case "$ci_host" in
         ;;
 esac
 
-make="make -j${ci_parallel} V=1 VERBOSE=1"
+# Allow overriding make (e.g. on FreeBSD it has to be set to gmake)
+: "${make:=make}"
+export MAKE=${make}
+make="${make} -j${ci_parallel} V=1 VERBOSE=1"
 
 case "$ci_buildsys" in
     (autotools)

tools/ci-install.sh

@@ -320,6 +320,7 @@ case "$ci_distro" in
             expat
             glib
             git
+            gmake
             libtool
             libX11
             libxslt