Generate a header containing git version info

It contains the last annotated tag, and possibly also the number of
commits since then and the hash of the last commit.

src/common/config/meson.build

@@ -0,0 +1,8 @@
+# Generate a file containing the last annotated git tag and possibly also the
+# amount of commits since then and the hash of the last commit
+vcs_tag(
+  command : ['git', 'describe', '--always'],
+  input : 'version.h.in',
+  output : 'version.h',
+  replace_string : '@VCS_VERSION@'
+)