Build fails on libm systems

[vpzomtrrfrt]

On Gentoo:

cc -g -O2 -std=gnu11 -Wvla -pedantic -Wall -Wextra -Wno-unused-parameter -Wno-unused-result -DGIT_TAG='"1fefa9e"'   -c -o bim.o bim.c
cc -rdynamic  bim.o  -l:libkuroko.a -ldl -lpthread -o bim
/usr/x86_64-pc-linux-gnu/binutils-bin/2.46.0/ld: /usr/local/lib/libkuroko.a(obj_numeric.o): in function `_krk_method_float___rfloordiv__':
/home/colin/kuroko/src/obj_numeric.c:809:(.text+0x1631): undefined reference to `floor'
/usr/x86_64-pc-linux-gnu/binutils-bin/2.46.0/ld: /usr/local/lib/libkuroko.a(obj_numeric.o): in function `_krk_method_float___floordiv__':
/home/colin/kuroko/src/obj_numeric.c:800:(.text+0x16ca): undefined reference to `floor'
/usr/x86_64-pc-linux-gnu/binutils-bin/2.46.0/ld: /usr/local/lib/libkuroko.a(obj_numeric.o): in function `_krk_method_int___floordiv__':
/home/colin/kuroko/src/obj_numeric.c:523:(.text+0x31f4): undefined reference to `floor'
/usr/x86_64-pc-linux-gnu/binutils-bin/2.46.0/ld: /usr/local/lib/libkuroko.a(obj_numeric.o): in function `_krk_method_int___rfloordiv__':
/home/colin/kuroko/src/obj_numeric.c:535:(.text+0x4d7c): undefined reference to `floor'
collect2: error: ld returned 1 exit status
make: *** [<builtin>: bim] Error 1

Seems to work fine if I add this:

diff --git a/Makefile b/Makefile
index 6306773..5e6b418 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@ ifeq (klange,$(shell echo $$USER))
   LDLIBS=../kuroko/libkuroko.a
 endif
 
-LDLIBS +=  -ldl -lpthread
+LDLIBS +=  -ldl -lpthread -lm
 
 prefix=/usr/local
 exec_prefix=$(prefix)

But a real solution probably needs to mirror the condition that kuroko uses since another libc might not use libm