diff -rupN --no-dereference qtbase-everywhere-src-5.13.2/qmake/generators/makefile.cpp qtbase-everywhere-src-5.13.2-new/qmake/generators/makefile.cpp
--- qtbase-everywhere-src-5.13.2/qmake/generators/makefile.cpp	2019-12-09 14:40:49.597520383 +0100
+++ qtbase-everywhere-src-5.13.2-new/qmake/generators/makefile.cpp	2019-12-09 14:40:49.600520416 +0100
@@ -3259,6 +3259,9 @@ MakefileGenerator::pkgConfigFileName(boo
         if (dot != -1)
             ret = ret.left(dot);
     }
+    if (project->isActiveConfig("debug")) {
+        ret += "d";
+    }
     ret += Option::pkgcfg_ext;
     QString subdir = project->first("QMAKE_PKGCONFIG_DESTDIR").toQString();
     if(!subdir.isEmpty()) {