Fix add_swift_target_library for the static SDK

add_swift_target_library was missing pieces for passing sources and
flags to the static SDK build. As a result, the static SDK was missing
pieces (specifically Mutex).

Also adding the Musl import to the Linux Mutex implementation.

Author: etcwilde

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -1929,6 +1929,7 @@ function(add_swift_target_library name)
         SWIFT_COMPILE_FLAGS_WATCHOS
         SWIFT_COMPILE_FLAGS_XROS
         SWIFT_COMPILE_FLAGS_LINUX
+        SWIFT_COMPILE_FLAGS_LINUX_STATIC
         SWIFT_MODULE_DEPENDS
         SWIFT_MODULE_DEPENDS_ANDROID
         SWIFT_MODULE_DEPENDS_CYGWIN
@@ -1959,6 +1960,7 @@ function(add_swift_target_library name)
         SWIFT_SOURCES_DEPENDS_FREEBSD
         SWIFT_SOURCES_DEPENDS_OPENBSD
         SWIFT_SOURCES_DEPENDS_LINUX
+        SWIFT_SOURCES_DEPENDS_LINUX_STATIC
         SWIFT_SOURCES_DEPENDS_CYGWIN
         SWIFT_SOURCES_DEPENDS_HAIKU
         SWIFT_SOURCES_DEPENDS_WASI
@@ -2212,6 +2214,9 @@ function(add_swift_target_library name)
     elseif(sdk STREQUAL "LINUX")
       list(APPEND swiftlib_swift_compile_flags_all
            ${SWIFTLIB_SWIFT_COMPILE_FLAGS_LINUX})
+    elseif(sdk STREQUAL "LINUX_STATIC")
+      list(APPEND swiftlib_swift_compile_flags_all
+           ${SWIFTLIB_SWIFT_COMPILE_FLAGS_LINUX_STATIC})
     elseif(sdk STREQUAL "WINDOWS")
       # FIXME: https://github.com/apple/swift/issues/44614
       # static and shared are not mutually exclusive; however since we do a
@@ -2256,6 +2261,8 @@ function(add_swift_target_library name)
       list(APPEND sources ${SWIFTLIB_SWIFT_SOURCES_DEPENDS_OPENBSD})
     elseif(sdk STREQUAL "LINUX" OR sdk STREQUAL "ANDROID")
       list(APPEND sources ${SWIFTLIB_SWIFT_SOURCES_DEPENDS_LINUX})
+    elseif(sdk STREQUAL "LINUX_STATIC")
+      list(APPEND sources ${SWIFTLIB_SWIFT_SOURCES_DEPENDS_LINUX_STATIC})
     elseif(sdk STREQUAL "CYGWIN")
       list(APPEND sources ${SWIFTLIB_SWIFT_SOURCES_DEPENDS_CYGWIN})
     elseif(sdk STREQUAL "HAIKU")

stdlib/public/Synchronization/CMakeLists.txt

@@ -94,6 +94,8 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
     ${SWIFT_SYNCHRONIZATION_DARWIN_SOURCES}
   SWIFT_SOURCES_DEPENDS_LINUX
     ${SWIFT_SYNCHRONIZATION_LINUX_SOURCES}
+  SWIFT_SOURCES_DEPENDS_LINUX_STATIC
+    ${SWIFT_SYNCHRONIZATION_LINUX_SOURCES}
   SWIFT_SOURCES_DEPENDS_WASI
     ${SWIFT_SYNCHRONIZATION_WASM_SOURCES}
   SWIFT_SOURCES_DEPENDS_WINDOWS
@@ -115,6 +117,8 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
     ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_LINUX
     Glibc
+  SWIFT_MODULE_DEPENDS_LINUX_STATIC
+    Musl
   SWIFT_MODULE_DEPENDS_ANDROID
     Android
   SWIFT_MODULE_DEPENDS_WINDOWS

stdlib/public/Synchronization/Mutex/LinuxImpl.swift

@@ -13,6 +13,8 @@
 import _SynchronizationShims
 #if canImport(Android)
 import Android
+#elseif canImport(Musl)
+import Musl
 #else
 import Glibc
 #endif