patch 8.2.3301: memory allocation functions don't have their own place

Problem:    Memory allocation functions don't have their own place.
Solution:   Move memory allocation functions to alloc.c.  (Yegappan
            Lakshmanan, closes #8717)
diff --git a/src/Make_ami.mak b/src/Make_ami.mak
index 678f999..12f7fe5 100644
--- a/src/Make_ami.mak
+++ b/src/Make_ami.mak
@@ -80,6 +80,7 @@
 
 # Common sources
 SRC += \
+	alloc.c \
 	arabic.c \
 	arglist.c \
 	autocmd.c \