patch 8.2.1640: Amiga: missing header for getgrgid()

Problem:    Amiga: missing header for getgrgid().
Solution:   Add the grp.h header. (Ola Söder, closes #6906)
diff --git a/src/os_amiga.h b/src/os_amiga.h
index 611555e..98f3cff 100644
--- a/src/os_amiga.h
+++ b/src/os_amiga.h
@@ -91,6 +91,7 @@
 # include <limits.h>
 # include <errno.h>
 # include <pwd.h>
+# include <grp.h>
 # include <dirent.h>
 #endif
 
diff --git a/src/version.c b/src/version.c
index 26a66f0..4f7de31 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1640,
+/**/
     1639,
 /**/
     1638,