I can understand you because it happen to me too, then makefile on tests was not cleaning the generated files ending with "-cc" and "-tcc" and if we've generated ones that worked before they will be used on tests instead of generating new ones with the modification we did to tinycc sources.
And yes I'm testing on ubuntu 12.04 X86_64.
I've added a commit to mob that do clean then, after that try "make clean", "make" and "make test" then you probably will get the segfault:
../tcc -B.. -I.. -I.. -I../include -o abitest-tcc abitest.c ../libtcc.c -I.. -Wall -g -O2 -fno-strict-aliasing -Wno-pointer-sign -Wno-sign-compare -Wno-unused-result -DCONFIG_LDDIR="\"lib\"" -DCONFIG_MULTIARCHDIR="\"x86_64-linux-gnu\"" -DTCC_TARGET_X86_64 -DONE_SOURCE -lm -ldl -I..
------------ abitest ------------
./abitest-cc lib_path=.. include="../include"
ret_int_test... success
ret_longlong_test... success
ret_float_test... success
ret_double_test... success
ret_longdouble_test... success
ret_2float_test... success
ret_2double_test... success
reg_pack_test... success
reg_pack_longlong_test... success
sret_test... success
one_member_union_test... success
two_member_union_test... success
many_struct_test... success
many_struct_test_2... success
stdarg_test... success
stdarg_struct_test... success
arg_align_test... success
./abitest-tcc lib_path=.. include="../include"
Segmentation fault (core dumped)
make[1]: *** [abitest] Error 139
make[1]: Leaving directory `/home/mingo/dev/c/tinycc/tests'
make: *** [test] Error 2