I see no getpid() or other requirement for process.h here.

trawick · trawick · commit f5c80663dfbc · 2011-03-11T20:30:42.000Z
(the include of process.h was added in r1025496) git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1080752 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/modules/http/chunk_filter.c b/modules/http/chunk_filter.c
@@ -38,10 +38,6 @@
 
 #include "mod_core.h"
 
-#if APR_HAVE_PROCESS_H
-#include <process.h>            /* for getpid() on Win32 */
-#endif
-
 /*
  * A pointer to this is used to memorize in the filter context that a bad
  * gateway error bucket had been seen. It is used as an invented unique pointer.
