When building the 10.6 branch I ran into the Following crash on OpenBSD with glxgears.  I didn't see the same with master.  My 10.6 has a few additional
patches to build on OpenBSD but none in src/mesa/drivers/dri/i965.

Starting program: /usr/X11R6/bin/glxgears 
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.

Program received signal SIGSEGV, Segmentation fault.
0x0000026dba64bd6a in brw::vec4_visitor::run (this=0x7f7ffffc5ca0) at brw_vec4.cpp:1714
1714       sanity_param_count = prog->Parameters->NumParameters;
Current language:  auto; currently c++
(gdb) bt
#0  0x0000026dba64bd6a in brw::vec4_visitor::run (this=0x7f7ffffc5ca0) at brw_vec4.cpp:1714
#1  0x0000026dba64c6f9 in brw_vs_emit (brw=0x26d720ed030, prog=0x26d1285ec30, c=0x7f7ffffc6ca0, 
    prog_data=0x7f7ffffc6bb0, mem_ctx=0x26cf41adb70, final_assembly_size=0x7f7ffffc6d54) at brw_vec4.cpp:1936
#2  0x0000026dba673238 in brw_codegen_vs_prog (brw=0x26d720ed030, prog=0x26d1285ec30, vp=0x26d25b66000, key=Variable "key" is not available.
)
    at brw_vs.c:293
#3  0x0000026dba6734a3 in brw_vs_precompile (ctx=0x26d720ed030, shader_prog=0x26d1285ec30, prog=0x26d25b66000)
    at brw_vs.c:529
#4  0x0000026dba640ca7 in brw_link_shader (ctx=0x26d720ed030, shProg=0x26d1285ec30) at brw_shader.cpp:84
#5  0x0000026dba427ee9 in _mesa_glsl_link_shader (ctx=0x26d720ed030, prog=0x26d1285ec30)
    at program/ir_to_mesa.cpp:2964
#6  0x0000026dba3357aa in link_program (ctx=0x26d720ed030, program=Variable "program" is not available.
) at main/shaderapi.c:946
#7  0x0000026dba425338 in meta_clear (ctx=0x26d720ed030, buffers=18, glsl=true) at drivers/common/meta.c:1546
#8  0x0000026dba57d809 in brw_clear (ctx=0x26d720ed030, mask=0) at brw_clear.c:263
#9  0x0000026aeab0302e in __register_frame_info () from /usr/X11R6/bin/glxgears
#10 0x0000026aeab03c6d in __register_frame_info () from /usr/X11R6/bin/glxgears
#11 0x0000026aeab01e31 in ?? () from /usr/X11R6/bin/glxgears
#12 0x0000000000000000 in ?? ()
(gdb) p prog
$1 = (gl_program * const) 0x0

Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel Open Source Technology Center (0x8086)
    Device: Mesa DRI Intel(R) Ironlake Mobile  (0x46)
    Version: 10.6.2
    Accelerated: yes
    Video memory: 192MB
    Unified memory: yes
    Preferred profile: compat (0x2)
    Max core profile version: 0.0
    Max compat profile version: 2.1
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 2.0
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Ironlake Mobile 
OpenGL version string: 2.1 Mesa 10.6.2 (git-e7f2411)
OpenGL shading language version string: 1.20