Use C++ style comments consistently in SDL source code

Implemented using this script:

find . -type f -exec sed -i'' -e 's,/\* *\([^*]*\)\*/ *$,// \1,' -e 's, \+$,,' {} \;
git checkout \
    core/linux/SDL_evdev_kbd_default_keymap.h \
    events/imKStoUCS.* \
    hidapi \
    joystick/controller_type.c \
    joystick/controller_type.h \
    joystick/hidapi/steam/controller_constants.h \
    joystick/hidapi/steam/controller_structs.h \
    joystick/SDL_gamepad_db.h \
    libm \
    render/*/*Shader*.h \
    render/vitagxm/SDL_render_vita_gxm_shaders.h \
    render/metal/SDL_shaders_metal_*.h \
    stdlib/SDL_malloc.c \
    stdlib/SDL_qsort.c \
    stdlib/SDL_strtokr.c \
    test/ \
    video/directx/SDL_d3d12_xbox_cmacros.h \
    video/directx/d3d12.h \
    video/directx/d3d12sdklayers.h \
    video/khronos \
    video/x11/edid-parse.c \
    video/x11/xsettings-client.* \
    video/yuv2rgb
sed -i'' -e 's,/\* *\([^*]*\)\*/ *$,// \1,' -e 's, \+$,,' hidapi/SDL_hidapi.c

src/thread/generic/SDL_syscond.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-/* An implementation of condition variables using semaphores and mutexes */
+// An implementation of condition variables using semaphores and mutexes
 /*
    This implementation borrows heavily from the BeOS condition variable
    implementation, written by Christopher Tate and Owen Smith.  Thanks!
@@ -49,7 +49,7 @@ typedef struct SDL_cond_generic
     SDL_Semaphore *wait_done;
 } SDL_cond_generic;
 
-/* Create a condition variable */
+// Create a condition variable
 SDL_Condition *SDL_CreateCondition_generic(void)
 {
     SDL_cond_generic *cond = (SDL_cond_generic *)SDL_calloc(1, sizeof(*cond));
@@ -70,7 +70,7 @@ SDL_Condition *SDL_CreateCondition_generic(void)
     return (SDL_Condition *)cond;
 }
 
-/* Destroy a condition variable */
+// Destroy a condition variable
 void SDL_DestroyCondition_generic(SDL_Condition *_cond)
 {
     SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
@@ -88,7 +88,7 @@ void SDL_DestroyCondition_generic(SDL_Condition *_cond)
     }
 }
 
-/* Restart one of the threads that are waiting on the condition variable */
+// Restart one of the threads that are waiting on the condition variable
 int SDL_SignalCondition_generic(SDL_Condition *_cond)
 {
     SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
@@ -114,7 +114,7 @@ int SDL_SignalCondition_generic(SDL_Condition *_cond)
     return 0;
 }
 
-/* Restart all threads that are waiting on the condition variable */
+// Restart all threads that are waiting on the condition variable
 int SDL_BroadcastCondition_generic(SDL_Condition *_cond)
 {
     SDL_cond_generic *cond = (SDL_cond_generic *)_cond;
@@ -189,10 +189,10 @@ int SDL_WaitConditionTimeoutNS_generic(SDL_Condition *_cond, SDL_Mutex *mutex, S
     ++cond->waiting;
     SDL_UnlockMutex(cond->lock);
 
-    /* Unlock the mutex, as is required by condition variable semantics */
+    // Unlock the mutex, as is required by condition variable semantics
     SDL_UnlockMutex(mutex);
 
-    /* Wait for a signal */
+    // Wait for a signal
     retval = SDL_WaitSemaphoreTimeoutNS(cond->wait_sem, timeoutNS);
 
     /* Let the signaler know we have completed the wait, otherwise
@@ -203,20 +203,20 @@ int SDL_WaitConditionTimeoutNS_generic(SDL_Condition *_cond, SDL_Mutex *mutex, S
      */
     SDL_LockMutex(cond->lock);
     if (cond->signals > 0) {
-        /* If we timed out, we need to eat a condition signal */
+        // If we timed out, we need to eat a condition signal
         if (retval > 0) {
             SDL_WaitSemaphore(cond->wait_sem);
         }
-        /* We always notify the signal thread that we are done */
+        // We always notify the signal thread that we are done
         SDL_SignalSemaphore(cond->wait_done);
 
-        /* Signal handshake complete */
+        // Signal handshake complete
         --cond->signals;
     }
     --cond->waiting;
     SDL_UnlockMutex(cond->lock);
 
-    /* Lock the mutex, as is required by condition variable semantics */
+    // Lock the mutex, as is required by condition variable semantics
     SDL_LockMutex(mutex);
 #endif
 

src/thread/generic/SDL_syscond_c.h

@@ -31,6 +31,6 @@ int SDL_SignalCondition_generic(SDL_Condition *cond);
 int SDL_BroadcastCondition_generic(SDL_Condition *cond);
 int SDL_WaitConditionTimeoutNS_generic(SDL_Condition *cond, SDL_Mutex *mutex, Sint64 timeoutNS);
 
-#endif /* SDL_THREAD_GENERIC_COND_SUFFIX */
+#endif // SDL_THREAD_GENERIC_COND_SUFFIX
 
-#endif /* SDL_syscond_generic_h_ */
+#endif // SDL_syscond_generic_h_

src/thread/generic/SDL_sysmutex.c

@@ -37,7 +37,7 @@ SDL_Mutex *SDL_CreateMutex(void)
 
 #ifndef SDL_THREADS_DISABLED
     if (mutex) {
-        /* Create the mutex semaphore, with initial value 1 */
+        // Create the mutex semaphore, with initial value 1
         mutex->sem = SDL_CreateSemaphore(1);
         mutex->recursive = 0;
         mutex->owner = 0;
@@ -78,7 +78,7 @@ void SDL_LockMutex(SDL_Mutex *mutex) SDL_NO_THREAD_SAFETY_ANALYSIS  // clang doe
             mutex->recursive = 0;
         }
     }
-#endif /* SDL_THREADS_DISABLED */
+#endif // SDL_THREADS_DISABLED
 }
 
 int SDL_TryLockMutex(SDL_Mutex *mutex)

src/thread/generic/SDL_syssem.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-/* An implementation of semaphores using mutexes and condition variables */
+// An implementation of semaphores using mutexes and condition variables
 
 #include "SDL_systhread_c.h"
 
@@ -111,7 +111,7 @@ int SDL_WaitSemaphoreTimeoutNS(SDL_Semaphore *sem, Sint64 timeoutNS)
         return SDL_InvalidParamError("sem");
     }
 
-    /* A timeout of 0 is an easy case */
+    // A timeout of 0 is an easy case
     if (timeoutNS == 0) {
         retval = SDL_MUTEX_TIMEDOUT;
         SDL_LockMutex(sem->count_lock);
@@ -169,4 +169,4 @@ int SDL_SignalSemaphore(SDL_Semaphore *sem)
     return 0;
 }
 
-#endif /* SDL_THREADS_DISABLED */
+#endif // SDL_THREADS_DISABLED

src/thread/generic/SDL_systhread.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-/* Thread management routines for SDL */
+// Thread management routines for SDL
 
 #include "../SDL_systhread.h"
 

src/thread/generic/SDL_systhread_c.h

@@ -20,5 +20,5 @@
 */
 #include "SDL_internal.h"
 
-/* Stub until we implement threads on this platform */
+// Stub until we implement threads on this platform
 typedef int SYS_ThreadHandle;