On a fresh install from mercurial on macosx.

./python -SE -m sysconfig --generate-posix-vars
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
Assertion failed: (compact->utf8_length == 0), function _PyUnicode_CheckConsistency, file Objects/unicodeobject.c, line 369.
make: *** [Lib/_sysconfigdata.py] Abort trap: 6

This is reproduced with the following mercurial changesets:

changeset 	reproduced
368a5d7d8a15	no (3.2 branch)
fafe12f2a030	no (3.2 branch)

4a5eafcdde11	yes
6b8dd7724ec0	yes
0df295d590a8	yes
7e576ad85663    yes (tip on default)

When compiled with pydebug I've got the following in gdb:

#0  0x00007fff86c0282a in __kill ()
#1  0x00007fff8e61aa9c in abort ()
#2  0x00007fff8e64d5de in __assert_rtn ()
#3  0x00000001000d5589 in _PyUnicode_CheckConsistency (op=0x101024c40, check_content=0) at unicodeobject.c:369
#4  0x00000001000df567 in unicode_dealloc (unicode=0x101024c40) at unicodeobject.c:1503
#5  0x000000010009f025 in _Py_Dealloc (op=0x101024c40) at object.c:1765
#6  0x000000010019df6a in decode_unicode (c=0x7fff5fbf6d58, s=0x10087cc36 "ois Pinard]\n\nHeaps are arrays for which a[k] <= a[2*k+1] and a[k] <= a[2*k+2] for\nall k, counting elements from 0.  For the sake of comparison,\nnon-existing elements are considered to be infinite.  Th"..., len=4720, rawmode=0, encoding=0x1002c6710 "utf-8") at ast.c:3759
#7  0x000000010019e3c6 in parsestr (c=0x7fff5fbf6d58, n=0x10103a118, bytesmode=0x7fff5fbf6944) at ast.c:3829
#8  0x000000010019e839 in parsestrplus (c=0x7fff5fbf6d58, n=0x10103a0d0, bytesmode=0x7fff5fbf6944) at ast.c:3874
#9  0x000000010019597a in ast_for_atom (c=0x7fff5fbf6d58, n=0x10103a0d0) at ast.c:1869
#10 0x000000010019744d in ast_for_power (c=0x7fff5fbf6d58, n=0x10103a088) at ast.c:2228
#11 0x0000000100197fa6 in ast_for_expr (c=0x7fff5fbf6d58, n=0x10103a088) at ast.c:2428
#12 0x0000000100198a11 in ast_for_testlist (c=0x7fff5fbf6d58, n=0x1007c1c90) at ast.c:2584
#13 0x0000000100198fbe in ast_for_expr_stmt (c=0x7fff5fbf6d58, n=0x10048b868) at ast.c:2680
#14 0x000000010019d248 in ast_for_stmt (c=0x7fff5fbf6d58, n=0x10048b868) at ast.c:3600
#15 0x0000000100191530 in PyAST_FromNode (n=0x10048b280, flags=0x7fff5fbf6f60, filename=0x100794ee0 "/Users/herve/Documents/workspace/mercurial_repository/python-vanilla/Lib/heapq.py", arena=0x10051f8f0) at ast.c:760
#16 0x000000010021b86f in PyParser_ASTFromFile (fp=0x7fff77c75140, filename=0x100794ee0 "/Users/herve/Documents/workspace/mercurial_repository/python-vanilla/Lib/heapq.py", enc=0x0, start=257, ps1=0x0, ps2=0x0, flags=0x7fff5fbf6f60, errcode=0x0, arena=0x10051f8f0) at pythonrun.c:1982
#17 0x00000001001f6d04 in parse_source_module (pathname=0x1007a5320, fp=0x7fff77c75140) at import.c:1186
#18 0x00000001001f822d in load_source_module (name=0x1007bd178, pathname=0x1007a5320, fp=0x7fff77c75140) at import.c:1509
#19 0x00000001001fd345 in load_module (name=0x1007bd178, fp=0x7fff77c75140, pathname=0x1007a5320, type=1, loader=0x0) at import.c:2477
#20 0x00000001002011f7 in import_submodule (mod=0x100340f80, subname=0x1007bd178, fullname=0x1007bd178) at import.c:3338
#21 0x00000001001ffb97 in load_next (mod=0x100340f80, altmod=0x100340f80, inputname=0x1007bd178, p_outputname=0x7fff5fbf7350, p_prefix=0x7fff5fbf7338) at import.c:3149
#22 0x00000001001fe5c7 in import_module_level (name=0x1007bd178, globals=0x10077cbe8, locals=0x10077cbe8, fromlist=0x100340f80, level=0) at import.c:2842
#23 0x00000001001feb00 in PyImport_ImportModuleLevelObject (name=0x1007bd178, globals=0x10077cbe8, locals=0x10077cbe8, fromlist=0x100340f80, level=0) at import.c:2904
#24 0x000000010019fd85 in builtin___import__ (self=0x100607420, args=0x10079e9f0, kwds=0x0) at bltinmodule.c:195
#25 0x0000000100096214 in PyCFunction_Call (func=0x100607510, arg=0x10079e9f0, kw=0x0) at methodobject.c:84
#26 0x0000000100010656 in PyObject_Call (func=0x100607510, arg=0x10079e9f0, kw=0x0) at abstract.c:2150
#27 0x00000001001c597d in PyEval_CallObjectWithKeywords (func=0x100607510, arg=0x10079e9f0, kw=0x0) at ceval.c:3932
#28 0x00000001001ba572 in PyEval_EvalFrameEx (f=0x10052f5d0, throwflag=0) at ceval.c:2332
#29 0x00000001001c3681 in PyEval_EvalCodeEx (_co=0x1007b9dc0, globals=0x10077cbe8, locals=0x10077cbe8, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, kwdefs=0x0, closure=0x0) at ceval.c:3426
#30 0x00000001001aaf0b in PyEval_EvalCode (co=0x1007b9dc0, globals=0x10077cbe8, locals=0x10077cbe8) at ceval.c:771
#31 0x00000001001f2d62 in PyImport_ExecCodeModuleObject (name=0x10077b9e0, co=0x1007b9dc0, pathname=0x10060ed60, cpathname=0x10060ed60) at import.c:868
#32 0x00000001001f820e in load_source_module (name=0x10077b9e0, pathname=0x1004bbbf8, fp=0x7fff77c750a8) at import.c:1505
#33 0x00000001001fd345 in load_module (name=0x10077b9e0, fp=0x7fff77c750a8, pathname=0x1004bbbf8, type=1, loader=0x0) at import.c:2477
#34 0x00000001001f8c71 in load_package (name=0x10077b9e0, pathname=0x1006ad6b8) at import.c:1640
#35 0x00000001001fd3a1 in load_module (name=0x10077b9e0, fp=0x0, pathname=0x1006ad6b8, type=5, loader=0x0) at import.c:2491
#36 0x00000001002011f7 in import_submodule (mod=0x100340f80, subname=0x10077b9e0, fullname=0x10077b9e0) at import.c:3338
#37 0x00000001001ffb97 in load_next (mod=0x100340f80, altmod=0x100340f80, inputname=0x100765510, p_outputname=0x7fff5fbf93c0, p_prefix=0x7fff5fbf93a8) at import.c:3149
#38 0x00000001001fe5c7 in import_module_level (name=0x100765510, globals=0x1006ac2f0, locals=0x1006ac2f0, fromlist=0x1007578b0, level=0) at import.c:2842
#39 0x00000001001feb00 in PyImport_ImportModuleLevelObject (name=0x100765510, globals=0x1006ac2f0, locals=0x1006ac2f0, fromlist=0x1007578b0, level=0) at import.c:2904
#40 0x000000010019fd85 in builtin___import__ (self=0x100607420, args=0x100760180, kwds=0x0) at bltinmodule.c:195
#41 0x0000000100096214 in PyCFunction_Call (func=0x100607510, arg=0x100760180, kw=0x0) at methodobject.c:84
#42 0x0000000100010656 in PyObject_Call (func=0x100607510, arg=0x100760180, kw=0x0) at abstract.c:2150
#43 0x00000001001c597d in PyEval_CallObjectWithKeywords (func=0x100607510, arg=0x100760180, kw=0x0) at ceval.c:3932
#44 0x00000001001ba572 in PyEval_EvalFrameEx (f=0x10052ae70, throwflag=0) at ceval.c:2332
#45 0x00000001001c3681 in PyEval_EvalCodeEx (_co=0x1007644c0, globals=0x1006ac2f0, locals=0x1006ac2f0, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, kwdefs=0x0, closure=0x0) at ceval.c:3426
#46 0x00000001001aaf0b in PyEval_EvalCode (co=0x1007644c0, globals=0x1006ac2f0, locals=0x1006ac2f0) at ceval.c:771
#47 0x00000001001f2d62 in PyImport_ExecCodeModuleObject (name=0x1006b04b8, co=0x1007644c0, pathname=0x1004bb748, cpathname=0x1004bb748) at import.c:868
#48 0x00000001001f820e in load_source_module (name=0x1006b04b8, pathname=0x1006b43b0, fp=0x7fff77c75010) at import.c:1505
#49 0x00000001001fd345 in load_module (name=0x1006b04b8, fp=0x7fff77c75010, pathname=0x1006b43b0, type=1, loader=0x0) at import.c:2477
#50 0x00000001002011f7 in import_submodule (mod=0x100340f80, subname=0x1006b04b8, fullname=0x1006b04b8) at import.c:3338
#51 0x00000001001ffb97 in load_next (mod=0x100340f80, altmod=0x100340f80, inputname=0x1006b04b8, p_outputname=0x7fff5fbfb310, p_prefix=0x7fff5fbfb2f8) at import.c:3149
#52 0x00000001001fe5c7 in import_module_level (name=0x1006b04b8, globals=0x1006ac1a8, locals=0x1006ac1a8, fromlist=0x100340f80, level=0) at import.c:2842
#53 0x00000001001feb00 in PyImport_ImportModuleLevelObject (name=0x1006b04b8, globals=0x1006ac1a8, locals=0x1006ac1a8, fromlist=0x100340f80, level=0) at import.c:2904
#54 0x000000010019fd85 in builtin___import__ (self=0x100607420, args=0x1006a6960, kwds=0x0) at bltinmodule.c:195
#55 0x0000000100096214 in PyCFunction_Call (func=0x100607510, arg=0x1006a6960, kw=0x0) at methodobject.c:84
#56 0x0000000100010656 in PyObject_Call (func=0x100607510, arg=0x1006a6960, kw=0x0) at abstract.c:2150
#57 0x00000001001c597d in PyEval_CallObjectWithKeywords (func=0x100607510, arg=0x1006a6960, kw=0x0) at ceval.c:3932
#58 0x00000001001ba572 in PyEval_EvalFrameEx (f=0x100529180, throwflag=0) at ceval.c:2332
#59 0x00000001001c3681 in PyEval_EvalCodeEx (_co=0x1006bd1c0, globals=0x1006ac1a8, locals=0x1006ac1a8, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, kwdefs=0x0, closure=0x0) at ceval.c:3426
#60 0x00000001001aaf0b in PyEval_EvalCode (co=0x1006bd1c0, globals=0x1006ac1a8, locals=0x1006ac1a8) at ceval.c:771
#61 0x00000001001f2d62 in PyImport_ExecCodeModuleObject (name=0x1006938c8, co=0x1006bd1c0, pathname=0x1004aead0, cpathname=0x1004aead0) at import.c:868
#62 0x00000001001f820e in load_source_module (name=0x1006938c8, pathname=0x1006ad040, fp=0x7fff77c74f78) at import.c:1505
#63 0x00000001001fd345 in load_module (name=0x1006938c8, fp=0x7fff77c74f78, pathname=0x1006ad040, type=1, loader=0x0) at import.c:2477
#64 0x00000001002011f7 in import_submodule (mod=0x100340f80, subname=0x1006938c8, fullname=0x1006938c8) at import.c:3338
#65 0x00000001001ffb97 in load_next (mod=0x100340f80, altmod=0x100340f80, inputname=0x1006938c8, p_outputname=0x7fff5fbfd260, p_prefix=0x7fff5fbfd248) at import.c:3149
#66 0x00000001001fe5c7 in import_module_level (name=0x1006938c8, globals=0x1006a0e78, locals=0x1006a0e78, fromlist=0x10063a1b0, level=0) at import.c:2842
#67 0x00000001001feb00 in PyImport_ImportModuleLevelObject (name=0x1006938c8, globals=0x1006a0e78, locals=0x1006a0e78, fromlist=0x10063a1b0, level=0) at import.c:2904
#68 0x000000010019fd85 in builtin___import__ (self=0x100607420, args=0x1006a6330, kwds=0x0) at bltinmodule.c:195
#69 0x0000000100096214 in PyCFunction_Call (func=0x100607510, arg=0x1006a6330, kw=0x0) at methodobject.c:84
#70 0x0000000100010656 in PyObject_Call (func=0x100607510, arg=0x1006a6330, kw=0x0) at abstract.c:2150
#71 0x00000001001c597d in PyEval_CallObjectWithKeywords (func=0x100607510, arg=0x1006a6330, kw=0x0) at ceval.c:3932
#72 0x00000001001ba572 in PyEval_EvalFrameEx (f=0x100528b00, throwflag=0) at ceval.c:2332
#73 0x00000001001c3681 in PyEval_EvalCodeEx (_co=0x1006a7700, globals=0x1006a0e78, locals=0x1006a0e78, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, kwdefs=0x0, closure=0x0) at ceval.c:3426
#74 0x00000001001aaf0b in PyEval_EvalCode (co=0x1006a7700, globals=0x1006a0e78, locals=0x1006a0e78) at ceval.c:771
#75 0x00000001001f2d62 in PyImport_ExecCodeModuleObject (name=0x100693380, co=0x1006a7700, pathname=0x1004ae520, cpathname=0x1004ae520) at import.c:868
#76 0x00000001001f820e in load_source_module (name=0x100693380, pathname=0x1004a8600, fp=0x7fff77c74ee0) at import.c:1505
#77 0x00000001001fd345 in load_module (name=0x100693380, fp=0x7fff77c74ee0, pathname=0x1004a8600, type=1, loader=0x0) at import.c:2477
#78 0x00000001002011f7 in import_submodule (mod=0x100340f80, subname=0x100693380, fullname=0x100693380) at import.c:3338
#79 0x00000001001ffb97 in load_next (mod=0x100340f80, altmod=0x100340f80, inputname=0x100693380, p_outputname=0x7fff5fbff1b0, p_prefix=0x7fff5fbff198) at import.c:3149
#80 0x00000001001fe5c7 in import_module_level (name=0x100693380, globals=0x1006a0d30, locals=0x1006a0d30, fromlist=0x10061c6f0, level=0) at import.c:2842
#81 0x00000001001feb00 in PyImport_ImportModuleLevelObject (name=0x100693380, globals=0x1006a0d30, locals=0x1006a0d30, fromlist=0x10061c6f0, level=0) at import.c:2904
#82 0x000000010019fd85 in builtin___import__ (self=0x100607420, args=0x100621b10, kwds=0x0) at bltinmodule.c:195
#83 0x0000000100096214 in PyCFunction_Call (func=0x100607510, arg=0x100621b10, kw=0x0) at methodobject.c:84
#84 0x0000000100010656 in PyObject_Call (func=0x100607510, arg=0x100621b10, kw=0x0) at abstract.c:2150
#85 0x0000000100010863 in call_function_tail (callable=0x100607510, args=0x100621b10) at abstract.c:2182
#86 0x0000000100010ab7 in PyObject_CallFunction (callable=0x100607510, format=0x1002e379f "OOOOi") at abstract.c:2206
#87 0x000000010020226c in PyImport_Import (module_name=0x100693380) at import.c:3533
#88 0x00000001001fdf6f in PyImport_ImportModule (name=0x1002cdeb8 "runpy") at import.c:2728
#89 0x00000001002484f1 in RunModule (modname=0x10048b0d0, set_argv0=1) at main.c:171
#90 0x000000010024a0a8 in Py_Main (argc=5, argv=0x10048b040) at main.c:663
#91 0x000000010000128b in main (argc=5, argv=0x7fff5fbffa40) at python.c:63

See #13241.