MinGW: Allow debug-and-release builds

Commit 4d289edb14aeb49 did disable debug-and-release
for MinGW completely. While it makes sense to change the
default, we should allow people to opt-in to old behavior
by explicitly setting '-debug-and-release'.

To allow differentiation between debug and release libraries
debug dll's (again) have a 'd' suffix.

Fixes: QTBUG-80792
Change-Id: I341b1a94788f490e975be6736159980cd9273f08
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

configure.json

@@ -776,8 +776,8 @@
         },
         "debug_and_release": {
             "label": "Compile libs in debug and release mode",
-            "autoDetect": "input.debug == ''",
-            "condition": "config.darwin || (config.win32 && !config.gcc)",
+            "autoDetect": "input.debug == '' && !(config.win32 && config.gcc)",
+            "condition": "config.darwin || config.win32",
             "output": [ "publicFeature", "publicQtConfig", "debugAndRelease" ]
         },
         "force_debug_info": {

mkspecs/features/qt_functions.prf

@@ -5,7 +5,7 @@ defineReplace(qtPlatformTargetSuffix) {
     else: CONFIG(debug, debug|release) {
         !debug_and_release|build_pass {
             mac: return($${suffix}_debug)
-            win32:!gcc: return($${suffix}d)
+            win32: return($${suffix}d)
         }
     }
     return($$suffix)