Simplify value of INSTALL (always 'cp').
Pass value of OPT from configure environment to Makefile.
Add check for limits.h.
Use <directory>/libreadline.a instead of -lreadline.
diff --git a/Makefile.in b/Makefile.in
index 66d05ec..04f7a47 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -51,7 +51,7 @@
 WITH=		
 
 # Compiler options passed to subordinate makes
-OPT=		-O
+OPT=		@OPT@
 
 # Subdirectories where to run make recursively
 SUBDIRS=	Parser Objects Python Modules