makefile: use LUA_PKGCONFIG to set Lua implementation

This breaks compat with the previous LUA_IMPLEMENTATION but gives more
flexibility in that user can specify the pkg-config package name
directly.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>

2 files changed, 16 insertions, 31 deletions

diff --git a/README b/README
index 9f26959..faf1851 100644
--- a/README
+++ b/README
@@ -38,14 +38,11 @@ If you'd like to compile without Lua support, you may use:
 
 And if you'd like to specify a Lua implementation, you may use:
 
-    $ make LUA_IMPLEMENTATION=JIT
+    $ make LUA_PKGCONFIG=lua5.1
 
-for using the LuaJIT project. Or:
-
-    $ make LUA_IMPLEMENTATION=VANILLA
-
-for the mainline Lua project. If you specify neither implementation, it will
-be auto-detected, preferring LuaJIT if both are present.
+If this is not specified, the Lua implementation will be auto-detected,
+preferring LuaJIT if many are present. Acceptable values are generally "lua",
+"luajit", "lua5.1", and "lua5.2".
 
 
 Dependencies
diff --git a/cgit.mk b/cgit.mk
index 3b8b79a..2e2992f 100644
--- a/cgit.mk
+++ b/cgit.mk
@@ -29,30 +29,18 @@ ifdef NO_LUA
 	LUA_MESSAGE := linking without specified Lua support
 	CGIT_CFLAGS += -DNO_LUA
 else
-LUAJIT_CFLAGS := $(shell pkg-config --cflags luajit 2>/dev/null)
-LUAJIT_LIBS := $(shell pkg-config --libs luajit 2>/dev/null)
-LUA_LIBS := $(shell pkg-config --libs lua 2>/dev/null)
-LUA_CFLAGS := $(shell pkg-config --cflags lua 2>/dev/null)
-ifeq (JIT,$(LUA_IMPLEMENTATION))
-	ifeq ($(strip $(LUAJIT_LIBS)),)
- 		$(error LuaJIT specified via LUA_IMPLEMENTATION=JIT, but library could not be found.)
-	endif
-	LUA_MESSAGE := linking with selected LuaJIT
-	CGIT_LIBS += $(LUAJIT_LIBS)
-	CGIT_CFLAGS += $(LUAJIT_CFLAGS)
-else ifeq (VANILLA,$(LUA_IMPLEMENTATION))
-	ifeq ($(strip $(LUA_LIBS)),)
- 		$(error Lua specified via LUA_IMPLEMENTATION=VANILLA, but library could not be found.)
-	endif
-	LUA_MESSAGE := linking with selected Lua
-	CGIT_LIBS += $(LUA_LIBS)
-	CGIT_LIBS += $(LUA_CFLAGS)
-else ifneq ($(strip $(LUAJIT_LIBS)),)
-	LUA_MESSAGE := linking with autodetected LuaJIT
-	CGIT_LIBS += $(LUAJIT_LIBS)
-	CGIT_CFLAGS += $(LUAJIT_CFLAGS)
-else ifneq ($(strip $(LUA_LIBS)),)
-	LUA_MESSAGE := linking with autodetected Lua
+ifeq ($(LUA_PKGCONFIG),)
+	LUA_PKGCONFIG := $(shell for pc in luajit lua lua5.2 lua5.1; do \
+			pkg-config --exists $$pc && echo $$pc && break; \
+			done)
+	LUA_MODE := autodetected
+else
+	LUA_MODE := specified
+endif
+ifneq ($(LUA_PKGCONFIG),)
+	LUA_MESSAGE := linking with $(LUA_MODE) $(LUA_PKGCONFIG)
+	LUA_LIBS := $(shell pkg-config --libs $(LUA_PKGCONFIG) 2>/dev/null)
+	LUA_CFLAGS := $(shell pkg-config --cflags $(LUA_PKGCONFIG) 2>/dev/null)
 	CGIT_LIBS += $(LUA_LIBS)
 	CGIT_CFLAGS += $(LUA_CFLAGS)
 else