diff --git a/stdlib/public/Platform/CMakeLists.txt b/stdlib/public/Platform/CMakeLists.txt
index 2da5058189234..d718f82a463aa 100644
--- a/stdlib/public/Platform/CMakeLists.txt
+++ b/stdlib/public/Platform/CMakeLists.txt
@@ -20,6 +20,7 @@ add_swift_target_library(swiftDarwin ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_
 add_swift_target_library(swiftGlibc ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OVERLAY
     Glibc.swift.gyb
     ${swift_platform_sources}
+    POSIXError.swift
 
     SWIFT_COMPILE_FLAGS "${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}"
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"