libsysprof-capture: wrap strdup to be NULL-safe

src/libsysprof-capture/sysprof-capture-condition.c

@@ -519,7 +519,7 @@ sysprof_capture_condition_new_where_file (const char *path)
     return NULL;
 
   self->type = SYSPROF_CAPTURE_CONDITION_WHERE_FILE;
-  self->u.where_file = strdup (path);
+  self->u.where_file = sysprof_strdup (path);
   if (self->u.where_file == NULL)
     {
       free (self);

src/libsysprof-capture/sysprof-capture-reader.c

@@ -284,7 +284,7 @@ sysprof_capture_reader_new (const char   *filename,
       return NULL;
     }
 
-  self->filename = strdup (filename);
+  self->filename = sysprof_strdup (filename);
 
   return self;
 }
@@ -1080,7 +1080,7 @@ sysprof_capture_reader_save_as (SysprofCaptureReader  *self,
     }
 
   if (self->filename == NULL)
-    self->filename = strdup (filename);
+    self->filename = sysprof_strdup (filename);
 
   close (fd);
 
@@ -1173,7 +1173,7 @@ sysprof_capture_reader_copy (SysprofCaptureReader *self)
   *copy = *self;
 
   copy->ref_count = 1;
-  copy->filename = strdup (self->filename);
+  copy->filename = sysprof_strdup (self->filename);
   copy->fd = fd;
   copy->end_time = self->end_time;
   copy->st_buf = self->st_buf;

src/libsysprof-capture/sysprof-macros-internal.h

@@ -73,3 +73,5 @@
     if (_p != NULL) \
       (destroy) (_p); \
   } while (0)
+
+#define sysprof_strdup(s) ((s) ? strdup(s) : NULL)