Choosing specific library versions (lua51 vs lua) for compilation

Question

Hi. I wanted to compile my own conky, and I came across the following problem:
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_map.o): In function `tolua_bnd_setpeer':
(.text+0x76): undefined reference to `lua_setfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_map.o): In function `tolua_bnd_getpeer':
(.text+0x62a): undefined reference to `lua_getfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_map.o): In function `tolua_dobuffer':
(.text+0x10b7): undefined reference to `luaL_loadbuffer'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_map.o): In function `tolua_dobuffer':
(.text+0x10d3): undefined reference to `lua_pcall'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_push.o): In function `tolua_pushusertype':
(.text+0x214): undefined reference to `lua_setfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_to.o): In function `tolua_tofieldnumber':
(.text+0x21e): undefined reference to `lua_tonumber'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_to.o): In function `tolua_tonumber':
(.text+0x44): undefined reference to `lua_tonumber'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `module_newindex_event':
(.text+0xb8): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `module_newindex_event':
(.text+0x139): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `module_index_event':
(.text+0x25b): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `module_index_event':
(.text+0x27e): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `do_operator':
(.text+0x378): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o):(.text+0x4b8): more undefined references to `lua_call' follow
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `storeatubox.constprop.3':
(.text+0x56a): undefined reference to `lua_getfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `storeatubox.constprop.3':
(.text+0x5b3): undefined reference to `lua_setfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `class_index_event':
(.text+0x639): undefined reference to `lua_getfenv'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `class_index_event':
(.text+0x888): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `class_newindex_event':
(.text+0x967): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `class_newindex_event':
(.text+0xa5f): undefined reference to `lua_call'
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../lib/libtolua++.a(tolua_event.o): In function `class_gc_event':
(.text+0xb59): undefined reference to `lua_call'
collect2: error: ld returned 1 exit status
make[2]: *** [conky] Error 1
make[2]: Leaving directory `/var/abs/local/conky/src/conky-1.9.0/src'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/var/abs/local/conky/src/conky-1.9.0/src'
make: *** [all-recursive] Error 1
It turns out I have both lua (5.2.2, installed together with awesome) and lua51. When I deinstall lua and leave only lua51, the build succeeds.
The question is - how, while having both luas installed, can I tell for compilation to use lua51 and not lua? Is there a generalized approach to that or is it application specific? Sorry for possibly dumb questions, I'm not very well-versed on the subject of compilation under Linux.
wujek

Answer 1

Just specify that on the linker line.  As you haven't shown your makefile, I'm not sure how you're doing it now, but either of the following changes would do it:
- pkg-config --libs lua
+ pkg-config --libs lua5.1
- LDFLAGS=-llua
+ LDFLAGS=-llua5.1
Or more generally:
sed -i 's/-llua/-llua5.1/g' /path/to/Makefile