Turn off safeseh for foundation on X86. (#567)

Because lld has safeseh enabled by default and fails with a special
icu data object file icudt69l_dat.obj.

Co-authored-by: Saleem Abdulrasool <[email protected]>

Author: hjyamauchi

build.ps1

@@ -809,6 +809,10 @@ function Build-Foundation($Arch, [switch]$Test = $false) {
         CMAKE_INSTALL_PREFIX = "$($Arch.SDKInstallRoot)\usr";
         CMAKE_SYSTEM_NAME = "Windows";
         CMAKE_SYSTEM_PROCESSOR = $Arch.CMakeName;
+        # Turn off safeseh for lld as it has safeseh enabled by default
+        # and fails with an ICU data object file icudt69l_dat.obj. This
+        # matters to X86 only.
+        CMAKE_Swift_FLAGS = if ($Arch -eq $ArchX86) { "-Xlinker /SAFESEH:NO" } else { "" };
         CURL_DIR = "$LibraryRoot\curl-7.77.0\usr\lib\$ShortArch\cmake\CURL";
         ICU_DATA_LIBRARY_RELEASE = "$LibraryRoot\icu-69.1\usr\lib\$ShortArch\sicudt69.lib";
         ICU_I18N_LIBRARY_RELEASE = "$LibraryRoot\icu-69.1\usr\lib\$ShortArch\sicuin69.lib";