patch 8.2.3114: Amiga-like systems: build error using stat()

Problem:    Amiga-like systems: build error using stat().
Solution:   Only build swapfile_process_running() on systems where it is
            actually used. (Ola Söder, closes #8519)
diff --git a/src/memline.c b/src/memline.c
index 0eac1cd..c2e1074 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -1104,6 +1104,7 @@
 # include <sys/sysinfo.h>
 #endif
 
+#if defined(UNIX) || defined(MSWIN)
 /*
  * Return TRUE if the process with number "b0p->b0_pid" is still running.
  * "swap_fname" is the name of the swap file, if it's from before a reboot then
@@ -1112,7 +1113,7 @@
     static int
 swapfile_process_running(ZERO_BL *b0p, char_u *swap_fname UNUSED)
 {
-#ifdef HAVE_SYSINFO_UPTIME
+# ifdef HAVE_SYSINFO_UPTIME
     stat_T	    st;
     struct sysinfo  sinfo;
 
@@ -1121,14 +1122,15 @@
     if (mch_stat((char *)swap_fname, &st) != -1
 	    && sysinfo(&sinfo) == 0
 	    && st.st_mtime < time(NULL) - (
-# ifdef FEAT_EVAL
+#  ifdef FEAT_EVAL
 		override_sysinfo_uptime >= 0 ? override_sysinfo_uptime :
-# endif
+#  endif
 		sinfo.uptime))
 	return FALSE;
-#endif
+# endif
     return mch_process_running(char_to_long(b0p->b0_pid));
 }
+#endif
 
 /*
  * Try to recover curbuf from the .swp file.