From my autobuild on master

cc1: warnings being treated as errors
In file included from vm-engine.c:133,
                 from vm.c:322:
vm-i-scheme.c: In function 'vm_regular_engine':
vm-i-scheme.c:437: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:437: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:439: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:439: warning: comparison is always true due to limited range of data type
In file included from vm-engine.c:133,
                 from vm.c:330:
vm-i-scheme.c: In function 'vm_debug_engine':
vm-i-scheme.c:437: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:437: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:439: warning: comparison is always true due to limited range of data type
vm-i-scheme.c:439: warning: comparison is always true due to limited range of data type
gmake[3]: *** [libguile_la-vm.lo] Error 1
gmake[3]: Leaving directory `/home/gdt/BUILD-GUILE-master/guile/libguile'
gmake[2]: *** [all] Error 2
gmake[2]: Leaving directory `/home/gdt/BUILD-GUILE-master/guile/libguile'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory `/home/gdt/BUILD-GUILE-master/guile'
gmake: *** [all] Error 2