Generate an error when the CPU parameter is not specified and cannot be determined

See #18640

build/bakefiles/common.bkl

@@ -396,6 +396,15 @@
         </set>
     </if>
 
+    <set var="TARGET_CPU_COMPFLAG"></set>
+    <if cond="FORMAT=='msvc'">
+        <set var="TARGET_CPU_COMPFLAG">
+            <if cond="TARGET_CPU==''">TARGET_CPU_COMPFLAG=0</if>
+            <if cond="TARGET_CPU=='' and VISUALSTUDIOPLATFORM=='x64'"></if>
+            <if cond="TARGET_CPU=='' and VISUALSTUDIOPLATFORM=='X64'"></if>
+        </set>
+    </if>
+
     <template id="common_settings">
         <debug-info>$(DEBUGINFO)</debug-info>
         <debug-runtime-libs>$(DEBUGRUNTIME)</debug-runtime-libs>
@@ -423,6 +432,7 @@
         <ldflags>$(WIN32_DPI_LINKFLAG)</ldflags>
         <if cond="FORMAT=='msvc'">
             <ldflags>$(LINK_TARGET_CPU)</ldflags>
+            <define>$(TARGET_CPU_COMPFLAG)</define>
         </if>
     </template>
 

include/wx/msw/chkconf.h

@@ -13,6 +13,13 @@
 #ifndef _WX_MSW_CHKCONF_H_
 #define _WX_MSW_CHKCONF_H_
 
+/* ensure that CPU parameter is specified (only nmake .vc makefile) */
+#ifdef _MSC_VER
+    #if defined(_WIN64) && defined(TARGET_CPU_COMPFLAG) && (TARGET_CPU_COMPFLAG == 0)
+        #error CPU must be defined
+    #endif
+#endif
+
 /* ensure that MSW-specific settings are defined */
 #ifndef wxUSE_ACTIVEX
 #    ifdef wxABORT_ON_CONFIG_ERROR