0ef66e98ccf4946a0e4513ab5fc157df0f0aca4e.diff

diff --git a/mkspecs/common/msvc-version.conf b/mkspecs/common/msvc-version.conf
index 3fb55c9d81..5805383a04 100644
--- a/mkspecs/common/msvc-version.conf
+++ b/mkspecs/common/msvc-version.conf
@@ -110,6 +110,12 @@ greaterThan(QMAKE_MSC_VER, 1909) {
         QMAKE_CXXFLAGS_CXX14 = -std:c++14
         QMAKE_CXXFLAGS_CXX1Z = -std:c++17
     }
+
+    # MSVC 2017 15.8+ fixed std::aligned_storage but compilation fails without
+    # this flag since the fix breaks binary compatibility.
+    greaterThan(QMAKE_MSC_VER, 1914) {
+        DEFINES += _ENABLE_EXTENDED_ALIGNED_STORAGE
+    }
 }
 
 greaterThan(QMAKE_MSC_VER, 1910) {
diff --git a/qmake/Makefile.win32 b/qmake/Makefile.win32
index 3abcc1f21c..5292332187 100644
--- a/qmake/Makefile.win32
+++ b/qmake/Makefile.win32
@@ -39,7 +39,7 @@ CFLAGS_BARE = -c -Fo./ -Fdqmake.pdb \
               -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_WARNINGS \
               -DQT_VERSION_STR=\"$(QT_VERSION)\" -DQT_VERSION_MAJOR=$(QT_MAJOR_VERSION) -DQT_VERSION_MINOR=$(QT_MINOR_VERSION) -DQT_VERSION_PATCH=$(QT_PATCH_VERSION) \
               -DQT_BUILD_QMAKE -DQT_BOOTSTRAPPED -DPROEVALUATOR_FULL \
-              -DQT_NO_FOREACH -DUNICODE
+              -DQT_NO_FOREACH -DUNICODE -D_ENABLE_EXTENDED_ALIGNED_STORAGE
 CFLAGS   = $(CFLAGS_PCH) $(CFLAGS_BARE) $(CFLAGS)
 
 CXXFLAGS_BARE = $(CFLAGS_BARE)