Somewhat based on Arch Linux' Lua patch.

diff -aur lua-5.1.2.orig/Makefile lua-5.1.2/Makefile
--- lua-5.1.2.orig/Makefile	2007-03-25 16:44:39.000000000 +0200
+++ lua-5.1.2/Makefile	2007-04-09 20:22:39.100496674 +0200
@@ -43,7 +43,7 @@
 # What to install.
 TO_BIN= lua luac
 TO_INC= lua.h luaconf.h lualib.h lauxlib.h ../etc/lua.hpp
-TO_LIB= liblua.a
+TO_LIB= liblua.a liblua.so.5.1
 TO_MAN= lua.1 luac.1
 
 # Lua version and release.
@@ -65,6 +65,7 @@
 	cd src && $(INSTALL_DATA) $(TO_LIB) $(INSTALL_LIB)
 	cd doc && $(INSTALL_DATA) $(TO_MAN) $(INSTALL_MAN)
+	ln -s liblua.so.5.1 $(INSTALL_LIB)/liblua.so
 
 ranlib:
 	cd src && cd $(INSTALL_LIB) && $(RANLIB) $(TO_LIB)
 
diff -aur lua-5.1.2.orig/etc/lua.pc lua-5.1.2/etc/lua.pc
--- lua-5.1.2.orig/etc/lua.pc	2007-03-23 20:58:49.000000000 +0100
+++ lua-5.1.2/etc/lua.pc	2007-04-09 20:00:26.642825529 +0200
@@ -8,7 +8,7 @@
 R= 5.1.2
 
 # grep '^INSTALL_.*=' ../Makefile | sed 's/INSTALL_TOP/prefix/'
-prefix= /usr/local
+prefix= /usr
 INSTALL_BIN= ${prefix}/bin
 INSTALL_INC= ${prefix}/include
 INSTALL_LIB= ${prefix}/lib
diff -aur lua-5.1.2.orig/src/Makefile lua-5.1.2/src/Makefile
--- lua-5.1.2.orig/src/Makefile	2007-03-25 16:49:23.000000000 +0200
+++ lua-5.1.2/src/Makefile	2007-04-09 20:20:37.073542755 +0200
@@ -8,7 +8,8 @@
 PLAT= none
 
 CC= gcc
-CFLAGS= -O2 -Wall $(MYCFLAGS)
+CFLAGS ?= -O2 -Wall
+CFLAGS += $(MYCFLAGS)
 AR= ar rcu
 RANLIB= ranlib
 RM= rm -f
@@ -23,6 +24,7 @@
 PLATS= aix ansi bsd freebsd generic linux macosx mingw posix solaris
 
 LUA_A=	liblua.a
+LUA_SO= liblua.so
 CORE_O=	lapi.o lcode.o ldebug.o ldo.o ldump.o lfunc.o lgc.o llex.o lmem.o \
 	lobject.o lopcodes.o lparser.o lstate.o lstring.o ltable.o ltm.o  \
 	lundump.o lvm.o lzio.o
@@ -36,7 +38,7 @@
 LUAC_O=	luac.o print.o
 
 ALL_O= $(CORE_O) $(LIB_O) $(LUA_O) $(LUAC_O)
-ALL_T= $(LUA_A) $(LUA_T) $(LUAC_T)
+ALL_T= $(LUA_A) $(LUA_SO) $(LUA_T) $(LUAC_T)
 ALL_A= $(LUA_A)
 
 default: $(PLAT)
@@ -51,6 +53,10 @@
 	$(AR) $@ $?
 	$(RANLIB) $@
 
+$(LUA_SO): $(CORE_O) $(LIB_O)
+	$(CC) -shared -Wl,-soname,liblua.so -o $@.5.1 $? $(MYLDFLAGS)
+	ln -s $@.5.1 $@
+
 $(LUA_T): $(LUA_O) $(LUA_A)
 	$(CC) -o $@ $(MYLDFLAGS) $(LUA_O) $(LUA_A) $(LIBS)
 
diff -aur lua-5.1.2.orig/src/luaconf.h lua-5.1.2/src/luaconf.h
--- lua-5.1.2.orig/src/luaconf.h	2007-03-24 04:01:55.000000000 +0100
+++ lua-5.1.2/src/luaconf.h	2007-04-09 20:01:00.274480800 +0200
@@ -94,7 +94,7 @@
 	".\\?.dll;"  LUA_CDIR"?.dll;" LUA_CDIR"loadall.dll"
 
 #else
-#define LUA_ROOT	"/usr/local/"
+#define LUA_ROOT	"/usr/"
 #define LUA_LDIR	LUA_ROOT "share/lua/5.1/"
 #define LUA_CDIR	LUA_ROOT "lib/lua/5.1/"
 #define LUA_PATH_DEFAULT  \