POSIX: guard the inclusion of pthread.h

Not all deployment targets use POSIX threads (pthreads).  Use the POSIX
mandated macro `_POSIX_THREADS` to detect whether POSIX threads are in
use.  Conditionally include `unistd.h` which is the Unix standard header
which provides the definition for `_POSIX_THREADS` if the platform uses
POSIX threads.  Unfortunately, clang does not define `__unix__` for
macOS (Bob Wilson does not recall why this was the case, and we have yet
to test if we can get away with defining `__unix__` for the platform
without breaking existing software).

Author: compnerd

CoreFoundation/AppServices.subproj/CFUserNotification.c

@@ -17,13 +17,18 @@
 #include "CFRuntime_Internal.h"
 #include <CoreFoundation/CFMachPort.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <stdio.h>
 #include <mach/mach.h>
 #include <mach/error.h>
 #include <limits.h>
 #include <errno.h>
+
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
+#endif
 
 #define CFUserNotificationLog(alertHeader, alertMessage) CFLog(3, CFSTR("%@:  %@"), alertHeader, alertMessage);
 

CoreFoundation/Base.subproj/CFBase.c

@@ -11,7 +11,10 @@
 #include <CoreFoundation/CFBase.h>
 #include "CFInternal.h"
 #include "CFRuntime_Internal.h"
-#if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI || DEPLOYMENT_TARGET_LINUX || DEPLOYMENT_TARGET_FREEBSD
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
 #endif
 #if DEPLOYMENT_TARGET_MACOSX || DEPLOYMENT_TARGET_EMBEDDED || DEPLOYMENT_TARGET_EMBEDDED_MINI

CoreFoundation/Base.subproj/CFInternal.h

@@ -101,13 +101,17 @@ CF_EXTERN_C_BEGIN
 #include <xlocale.h>
 #endif // !TARGET_OS_CYGWIN && !defined(__linux__)
 
-#include <unistd.h>
 #include <sys/time.h>
 #include <signal.h>
 #include <stdio.h>
 #endif // TARGET_OS_MAC || TARGET_OS_LINUX || TARGET_OS_BSD
 
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
+#endif
 
 #if !DEPLOYMENT_RUNTIME_SWIFT && __has_include(<os/log.h>)
 #include <os/log.h>

CoreFoundation/Base.subproj/CFPriv.h

@@ -567,7 +567,10 @@ CF_EXPORT CFMessagePortRef _CFMessagePortCreateLocalEx(CFAllocatorRef allocator,
 
 #endif
 
-#if TARGET_OS_MAC || TARGET_OS_EMBEDDED || TARGET_OS_IPHONE
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
 #elif !TARGET_OS_LINUX
 // Avoid including the pthread header

CoreFoundation/Base.subproj/CFUtilities.c

@@ -40,7 +40,6 @@
 #include <unistd.h>
 #include <sys/uio.h>
 #include <mach/mach.h>
-#include <pthread.h>
 #include <mach-o/loader.h>
 #include <mach-o/dyld.h>
 #include <crt_externs.h>
@@ -61,12 +60,15 @@
 
 #if DEPLOYMENT_TARGET_LINUX || DEPLOYMENT_TARGET_FREEBSD
 #include <string.h>
-#include <pthread.h>
 #include <sys/mman.h>
-#include <unistd.h>
 #endif
 
-
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
+#include <pthread.h>
+#endif
 
 
 

CoreFoundation/Base.subproj/CoreFoundation_Prefix.h

@@ -318,7 +318,6 @@ CF_EXPORT int _NS_access(const char *name, int amode);
 #define FD_SETSIZE 1024
 #include <winsock2.h>
 #include <windows.h>
-#include <pthread.h>
 
 #undef BOOL
 

CoreFoundation/Base.subproj/ForSwiftFoundationOnly.h

@@ -26,7 +26,12 @@
 #include <CoreFoundation/CFURLSessionInterface.h>
 #include <CoreFoundation/ForFoundationOnly.h>
 #include <fts.h>
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
+#endif
 #include <dirent.h>
 
 #include <CoreFoundation/CFCalendar_Internal.h>

CoreFoundation/RunLoop.subproj/CFRunLoop.c

@@ -19,7 +19,13 @@
 #include <math.h>
 #include <stdio.h>
 #include <limits.h>
+
+#if __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
+#if _POSIX_THREADS
 #include <pthread.h>
+#endif
 #if __HAS_DISPATCH__
 #include <dispatch/dispatch.h>
 #endif