guile: needs strtol_l, not available for musl

Fixes:
http://autobuild.buildroot.net/results/861/861c3038dff03ded6d97b8bb61ba8754dc21c7f8/
http://autobuild.buildroot.net/results/cd3/cd3377585e4fa5c7457c50e827d96adeceaac04b/
http://autobuild.buildroot.net/results/b45/b453c419292dba39aaa309ea057e56662e9af2f6/



Musl doesn't implement strtol_l, which is used by guile.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>