fix: compile x86 and forwarding dlls properly

That platform name is called Win32 in ICU
also fix a path

Used more flags that MS upstream did

Remove entrypoint from forwarding dlls

.github/workflows/build.yml

@@ -38,8 +38,8 @@ jobs:
     - name: Build entire Solution x86
       run: |
         $env:ICU_DATA_FILTER_FILE = '${{ github.workspace }}/build/filters/filter.json'
-        msbuild icu4c/source/allinone/allinone.sln /p:Configuration=Release /p:Platform=x86 /p:SkipUWP=true
-        msbuild icu/icu4c/source/common-and-i18n/combined.vcxproj /p:Configuration=Release /p:Platform=x86
+        msbuild icu/icu4c/source/allinone/allinone.sln /p:Configuration=Release /p:Platform=Win32 /p:SkipUWP=true
+        msbuild icu/icu4c/source/common-and-i18n/combined.vcxproj /p:Configuration=Release /p:Platform=Win32
       # The following tests fail with this error, the x64 passes.
       #  testing ICU in "D:\a\microsoft-icu\microsoft-icu\icu\icu4c\source\allinone\"\..\..  arch=x86 type=Release
       # ==== icuinfo =========================================================================

build/scripts/build_forwarding_dlls.bat

@@ -30,7 +30,7 @@ echo. Got Library: %~1
 del cmemory.obj %~1.dll %~1.lib %~1.exp ucln_cmn.lib ucln_cmn.exp ucln_cmn.obj umutex.obj utrace.obj
 :: Generate a .lib with the required forwarding rules
 lib /MACHINE:%arch% /nologo /def:..\common-and-i18n\%~1.def
-:: Generate a .dll with all of the implementations for dll export (implemented in ucln_cmn.cpp + deps) as well as the lib above
-cl /nologo /LD /DU_COMMON_IMPLEMENTATION /DU_EXPORT_2= /DU_EXPORT= /DU_PLATFORM_HAS_WIN32_API ucln_cmn.cpp cmemory.cpp umutex.cpp utrace.cpp %~1.lib /link /def:..\common-and-i18n\%~1.def /out:%~1.dll /MACHINE:%arch% /DLL
+:: Generate a .dll with just the .exp generated above, no code - just forward
+link %1.exp /NOENTRY /nologo /out:%~1.dll /MACHINE:%arch% /DLL /release /SUBSYSTEM:CONSOLE /guard:cf
 move %~1.dll %out_dir%\%~1.dll
 :goto :eof

icu/icu4c/source/common-and-i18n/combined.vcxproj

@@ -70,7 +70,8 @@
       <ImportLibrary>..\..\$(IcuLibOutputDir)\icu.lib</ImportLibrary>
       <!-- MSFT-Change: This forces dynamic linking of the UCRT. -->
       <IgnoreSpecificDefaultLibraries>libucrtd.lib;libucrt.lib</IgnoreSpecificDefaultLibraries>
-      <AdditionalOptions>/DEFAULTLIB:ucrtd.lib /def:icu.def %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions>/DEFAULTLIB:ucrtd.lib /def:icu.def /release /guard:cf %(AdditionalOptions)</AdditionalOptions>
+		  <SubSystem>Console</SubSystem>
     </Link>
   </ItemDefinitionGroup>
   <!-- Options that are common to all 'Release' project configurations -->
@@ -86,7 +87,8 @@
       <ImportLibrary>..\..\$(IcuLibOutputDir)\icu.lib</ImportLibrary>
       <!-- MSFT-Change: This forces dynamic linking of the UCRT. -->
       <IgnoreSpecificDefaultLibraries>libucrtd.lib;libucrt.lib</IgnoreSpecificDefaultLibraries>
-      <AdditionalOptions>/DEFAULTLIB:ucrt.lib /def:icu.def %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions>/DEFAULTLIB:ucrt.lib /def:icu.def /release /guard:cf %(AdditionalOptions)</AdditionalOptions>
+	    <SubSystem>Console</SubSystem>
       <!-- FIXME: Also filter out IGNORE_WINDOWS_HEADERS? -->
     </Link>
   </ItemDefinitionGroup>