Makefile: Add support for multiple Lua versions

Makefile

@@ -1,18 +1,23 @@
-LUA_VER    ?= $(shell lua -e 'print (_VERSION:match("Lua (.+)"))')
+LUA        ?= lua
+LUA_VER    ?= $(shell $(LUA) -e 'print (_VERSION:match("Lua (.+)") )')
 LIBDIR     ?= /usr/local/lib
 LUA_OBJDIR ?= $(LIBDIR)/lua/$(LUA_VER)
 PREFIX     ?= /usr/local
 
 LUA_PKG_NAME := $(shell \
-	   pkg-config --exists lua$(LUA_VER) && echo lua$(LUA_VER) \
-	|| pkg-config --exists lua && echo lua)
+	   (pkg-config --exists lua$(LUA_VER) && echo lua$(LUA_VER)) \
+	|| (pkg-config --exists lua && echo lua) )
 
 ifeq ($(LUA_PKG_NAME),)
 	$(error "No Lua pkg-config file found!")
 endif
 
-override CFLAGS+=  -Wall -ggdb $(shell pkg-config --cflags $(LUA_PKG_NAME))
-override LDFLAGS+= $(shell pkg-config --libs $(LUA_PKG_NAME))
+
+LUA_CFLAGS := $(shell pkg-config --cflags $(LUA_PKG_NAME))
+LUA_LIBS :=   $(shell pkg-config --libs $(LUA_PKG_NAME))
+
+override CFLAGS+=  -Wall -ggdb $(LUA_CFLAGS)
+override LDFLAGS+= $(LUA_LIBS)
 
 .SUFFIXES: .c .o .so
 
@@ -23,7 +28,7 @@ affinity.so: lua-affinity.o cpuset-str.o
 	$(CC) -shared -o $*.so $^ $(LDFLAGS)
 
 check: affinity.so
-	@tests/test.lua
+	$(LUA) tests/test.lua
 
 check-coverage:
 	make clean