[Piglit] [PATCH] README: correct flags for 32-on-64 build

[Constantine Charlamov]

On 03.03.2017 07:54, Brian Paul wrote:
>> On Thu, Mar 2, 2017 at 9:24 PM, Constantine Charlamov <Hi-Angel at yandex.ru <mailto:Hi-Angel at yandex.ru>> wrote:
>> 
>>     So far this is the only options I found to build 32-on-64. It supersedes
>>     the prev. patch to README — turns out, replacing i386→x86 isn't enough.
>>     The inconsistent resuls were because cmake retains options used for old
>>     runs. This patch was tested by completely removing piglit, and git
>>     cloning it againg.
>> 
>> 
>> "results" and "again"
>> 
>>  
>> 
>> 
>>     Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100017 <https://bugs.freedesktop.org/show_bug.cgi?id=100017>
>>     Signed-off-by: Constantine Charlamov <Hi-Angel at yandex.ru <mailto:Hi-Angel at yandex.ru>>
>>     Supersedes: https://patchwork.freedesktop.org/patch/141700/ <https://patchwork.freedesktop.org/patch/141700/>
>>     ---
>>      README | 3 ++-
>>      1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>>     diff --git a/README b/README
>>     index 23ae46352..e6667abda 100644
>>     --- a/README
>>     +++ b/README
>>     @@ -89,7 +89,8 @@ Now build everything:
>>      -------------------
>> 
>>      On Linux, if cross-compiling a 32-bit build on a 64-bit host, then you must
>>     -invoke cmake with option "-DCMAKE_SYSTEM_PROCESSOR=i386".
>>     +invoke cmake with options "-DCMAKE_SYSTEM_PROCESSOR=x86 -DCMAKE_C_FLAGS=-m32
>>     +-DCMAKE_CXX_FLAGS=-m32".
> 
> 
> Perhaps we should also document that it's necessary to do this in a clean tree, otherwise the build will likely fail if a 64-bit build was previously made.  That might save someone the effort that you went through.
> 
> BTW, did you try 'make clean' and 'rm CMakeCache.txt' before doing the 32-bit build?
> 
> -Brian

`make clean` doesn't work, but removing CMakeCache.txt seems does. I just
removed it, restarted the build, and it indeed started checking for
dependencies, which are usually cached after the first successful run.