Merge pull request #12535 from aschwaighofer/swift-4.1-branch-disable-signaling-nan-test-i386

Disable signaling NaN tests on i386
diff --git a/utils/build-script-impl b/utils/build-script-impl
index 5a65bba..1d15175 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -2545,7 +2545,8 @@
                     -DCMAKE_C_COMPILER:PATH="${LLVM_BIN}/clang"
                     -DCMAKE_CXX_COMPILER:PATH="${LLVM_BIN}/clang++"
                     -DCMAKE_SWIFT_COMPILER:PATH="${SWIFTC_BIN}"
-                    -DCMAKE_INSTALL_PREFIX:PATH="$(get_host_install_destdir ${host})$(get_host_install_prefix ${host})"
+                    -DCMAKE_INSTALL_PREFIX:PATH="$(get_host_install_prefix ${host})"
+                    -DCMAKE_INSTALL_LIBDIR:PATH="lib"
 
                     -DENABLE_SWIFT=YES
                     -DSWIFT_RUNTIME_LIBDIR:PATH="${SWIFT_BUILD_PATH}/lib/swift/${SWIFT_HOST_VARIANT}/${SWIFT_HOST_VARIANT_ARCH}"