Show information about flex (version and command path) in meson output

Like bison, this is useful to know which version and command of flex are
detected by meson.  For example, this was useful for me when using
win_flex.exe on Windows.

Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/[email protected]

diff --git a/meson.build b/meson.build
index aaa9daf266f17c2119ca9dbe7685d050ba1f1d4f..3ea4b0d72a09ae8441e8a42619ebd4e71bcce276 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -361,6 +361,10 @@ bison_kw = {
 }
 
 flex_flags = []
+if flex.found()
+  flex_version_c = run_command(flex, '--version', check: true)
+  flex_version = flex_version_c.stdout().split(' ')[1].split('\n')[0]
+endif
 flex_wrapper = files('src/tools/pgflex')
 flex_cmd = [python, flex_wrapper,
   '--builddir', '@BUILD_ROOT@',
@@ -3370,6 +3374,7 @@ if meson.version().version_compare('>=0.57')
     {
       'bison': '@0@ @1@'.format(bison.full_path(), bison_version),
       'dtrace': dtrace,
+      'flex': '@0@ @1@'.format(flex.full_path(), flex_version),
     },
     section: 'Programs',
   )