Print the Wine version at Meson configure time

CHANGELOG.md

@@ -6,6 +6,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic
 Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+
+- When building the package from source, the targetted Wine version gets printed
+  at configure-time. This can make it a bit easier to diagnose Wine-related
+  compilation issues.
+
 ## [3.1.0] - 2021-04-15
 
 ### Added

meson.build

@@ -68,14 +68,23 @@ endif
 # convention to be specified on the `main()` functions or else `argc` and `argv`
 # will point to the wrong memory. Similarly, with other versions of Wine this
 # should _not_ be specified for the same reason. We'll try to figure out the
-# current Wine version and add this calling convention based on that.
+# current Wine version and add this calling convention based on that. Also,
+# printing the configure-time Wine version might be useful in diagnosing build
+# issues so we'll do just that. The regexp looks a bit weird because of the
+# lookahead. That's purely for aesthetics so we don't end up printing trailing
+# dots when parsing Wine version strings like `wine-6.4.r0.g7ec998e1 ( TkG Staging Esync Fsync )`.
 #
 # https://bugs.winehq.org/show_bug.cgi?id=49138
-wine_version = run_command('sh', '-c', '''wine --version | grep --only-matching -E '[0-9]+\.[0-9.]+' | head -n1''')
-if wine_version.returncode() == 0 and \
-   wine_version.stdout().version_compare('>=5.7') and \
-   wine_version.stdout().version_compare('<6.0')
-  compiler_options += '-DWINE_USE_CDECL'
+wine_version = run_command('sh', '-c', '''wine --version | grep --only-matching -P '[0-9]+\.[0-9.]+?(?=\.)?' | head -n1''')
+if wine_version.returncode() == 0
+  message('Targetting Wine @0@'.format(wine_version.stdout()))
+  if wine_version.stdout().version_compare('>=5.7') and \
+     wine_version.stdout().version_compare('<6.0')
+    message('- Using the cdecl calling convention')
+    compiler_options += '-DWINE_USE_CDECL'
+  endif
+else
+  warning('Unable to determine the current Wine version')
 endif
 
 # Wine versions below 5.7 will segfault in `CoCreateGuid` which gets called