lua-lzlib: fix build failure, honor cflags, cleanup

* fix failure on buildbot where lua devel files are searched in home directory
 * add a patch to pass proper target optimization flags
 * remove unused PKG_INSTALL & Build/Install

Signed-off-by: Nicolas Thill <nico@openwrt.org>

lang/lua-lzlib/patches/001-allow_optim_flags.patch

@@ -0,0 +1,12 @@
+--- a/Makefile
++++ b/Makefile
+@@ -14,7 +14,8 @@ LUABIN= $(LUA)/bin
+ ZLIB=../zlib-1.2.3
+ 
+ # no need to change anything below here
+-CFLAGS= $(INCS) $(DEFS) $(WARN) -O0 -fPIC
++CFLAGS= $(INCS) $(DEFS) $(WARN) $(OFLAGS) -fPIC
++OFLAGS= -O0
+ WARN= -g -Werror -Wall -pedantic #-ansi
+ INCS= -I$(LUAINC) -I$(ZLIB)
+ LIBS= -L$(ZLIB) -lz -L$(LUALIB) -L$(LUABIN) #-llua51