Add support for clang -- error: ld: error: undefined symbol: clog10

[yonas]

Clang doesn't have clog10. I think it's specific to gcc.

442 / 476 #0 Updated file:/usr/include/sys/filio.h to iteration 1
443 / 477 #0 Updated file:/usr/include/sys/sockio.h to iteration 1
444 / 478 #0 Updated file:/usr/include/poll.h to iteration 1
445 / 478 #0 Updated scan:file:obj/linenoise.c::INCLUDES to iteration 1
446 / 478 #0 Updated file:obj/linenoise.o to iteration 1
447 / 478 #0 Updated file:lib/libminilang.a to iteration 1
448 / 479 #0 Updated symb:/obj/LDFLAGS to iteration 1
ld: error: undefined symbol: clog10
>>> referenced by ml_math.c:327 (/memfs/git/minilang/src/ml_math.c:327)
>>>               ml_math.o:(ml_method_fn_327_30) in archive /memfs/git/minilang/lib/libminilang.a
>>> referenced by ml_math.c:327 (/memfs/git/minilang/src/ml_math.c:327)
>>>               ml_math.o:(ml_method_fn_327_31) in archive /memfs/git/minilang/lib/libminilang.a
>>> did you mean: log10
>>> defined in: /usr/lib/libm.so
cc: error: linker command failed with exit code 1 (use -v to see invocation)
Error: file:bin/minilang: process returned non-zero exit code
        cc -o /memfs/git/minilang/bin/minilang /memfs/git/minilang/obj/minilang.o /memfs/git/minilang/lib/libminilang.a -lm -g -lyajl -lexpat -ldl -luuid -licuuc -L/usr/local/lib -lgc-threaded:1

FreeBSD clang version 13.0.0 (git@github.com:llvm/llvm-project.git llvmorg-13.0.0-0-gd7b669b3a303)
Target: x86_64-unknown-freebsd13.1
Thread model: posix
InstalledDir: /usr/bin

FreeBSD 13.1-RELEASE