How do you build this from a fresh git clone?

[lassik]

It's missing some configure scripts and autoreconf fails:

cd stage0 && autoreconf --install
 ---> Running in 3dfadfff9612
aclocal: warning: autoconf input should be named 'configure.ac', not 'configure.in'
configure.in:139: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2514: _AC_PREPROC_IFELSE is expanded from...
../../lib/autoconf/general.m4:2529: AC_PREPROC_IFELSE is expanded from...
configure.in:139: the top level
configure.in:139: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2514: _AC_PREPROC_IFELSE is expanded from...
../../lib/autoconf/general.m4:2529: AC_PREPROC_IFELSE is expanded from...
configure.in:139: the top level
configure.in:139: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2514: _AC_PREPROC_IFELSE is expanded from...
../../lib/autoconf/general.m4:2529: AC_PREPROC_IFELSE is expanded from...
configure.in:139: the top level
configure.in:139: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2514: _AC_PREPROC_IFELSE is expanded from...
../../lib/autoconf/general.m4:2529: AC_PREPROC_IFELSE is expanded from...
configure.in:139: the top level
autoheader: warning: missing template: ACCUM_BYTECODE_CORRELATION
autoheader: Use AC_DEFINE([ACCUM_BYTECODE_CORRELATION], [], [Description])
autoheader: warning: missing template: ACCUM_GF_CACHE_HISTOGRAM
autoheader: warning: missing template: CPP_SUPPORTS_ISYSTEM
autoheader: warning: missing template: DEBUG_BCI
autoheader: warning: missing template: FCANGET_DO_SELECT
autoheader: warning: missing template: FCANGET_USE_CNT
autoheader: warning: missing template: FCANGET_USE_IO_READ_PTR
autoheader: warning: missing template: FCANGET_USE_R
autoheader: warning: missing template: FULL_NUMERIC_TOWER
autoheader: warning: missing template: HAVE_SOCKLEN_T
autoheader: warning: missing template: HAVE_STRUCT_TIMEVAL
autoheader: warning: missing template: INCLUDE_PSTORE_UNMAPPER
autoheader: warning: missing template: INCLUDE_READ_BARRIER
autoheader: warning: missing template: NTOH_PROTO_OK
autoheader: warning: missing template: PLATFORM_ARCH_ALPHA
autoheader: warning: missing template: PLATFORM_ARCH_I386
autoheader: warning: missing template: PLATFORM_ARCH_M68K
autoheader: warning: missing template: PLATFORM_ARCH_MIPS
autoheader: warning: missing template: PLATFORM_ARCH_PPC
autoheader: warning: missing template: PLATFORM_ARCH_S390
autoheader: warning: missing template: PLATFORM_ARCH_SPARC
autoheader: warning: missing template: PLATFORM_ARCH_UNKNOWN
autoheader: warning: missing template: PLATFORM_ARCH_X86_64
autoheader: warning: missing template: PROFILING_HOOKS
autoheader: warning: missing template: SPRINTF_RETURNS_INT
autoheader: warning: missing template: TRACE_SIGNAL_LATENCY
autoheader: warning: missing template: USE_COMPUTED_GOTO
autoheader: warning: missing template: USE_NETINET_FOR_NTOH_PROTO
autoheader: warning: missing template: USE_POSIX_SIGNALS
autoheader: warning: missing template: USE_TIMEOFDAY_CLOCK
autoheader: warning: missing template: USE_i586_CLOCK
autoheader: warning: missing template: UTF_PROCESS_CODE
autoreconf: /usr/bin/autoheader failed with exit status: 1