prerequisites page

prerequisites page

[Todd Rinaldo]

I'm writing to report a discrepancy in http://gcc.gnu.org/install/prerequisites.html

I just discovered that if gmp is boot strapped during gcc build and an older m4 exists, when gmp calls flex, it will fail during configure with:

checking for flex... flex
checking lex output file root... configure: error: cannot find output from flex; giving up

I mention this because the prerequisites page specifies m4 as optional if you're just building gcc. m4 appears to have a minimal requirement if gmp is being boot strapped.

m4 requirement (was: prerequisites page)

[Gerald Pfeifer]

Todd,

On Wed, 19 May 2010, Todd Rinaldo wrote:
> I'm writing to report a discrepancy in 
> http://gcc.gnu.org/install/prerequisites.html
> 
> I just discovered that if gmp is boot strapped during gcc build and an 
> older m4 exists, when gmp calls flex, it will fail during configure 
> with:
> 
> checking for flex... flex
> checking lex output file root... configure: error: cannot find output from flex; giving up
> 
> I mention this because the prerequisites page specifies m4 as optional 
> if you're just building gcc. m4 appears to have a minimal requirement if 
> gmp is being boot strapped.

thanks for the report, Todd.  You mention m4, yet the output you show
is around flex?  

I can update our documentation, but need more details and confirmation
by the respective GCC maintainers on what exactly to adjust.

Gerald

Re: m4 requirement (was: prerequisites page)

[Todd Rinaldo]

On Jul 10, 2010, at 7:07 PM, Gerald Pfeifer wrote:

> Todd,
> 
> On Wed, 19 May 2010, Todd Rinaldo wrote:
>> I'm writing to report a discrepancy in 
>> http://gcc.gnu.org/install/prerequisites.html
>> 
>> I just discovered that if gmp is boot strapped during gcc build and an 
>> older m4 exists, when gmp calls flex, it will fail during configure 
>> with:
>> 
>> checking for flex... flex
>> checking lex output file root... configure: error: cannot find output from flex; giving up
>> 
>> I mention this because the prerequisites page specifies m4 as optional 
>> if you're just building gcc. m4 appears to have a minimal requirement if 
>> gmp is being boot strapped.
> 
> thanks for the report, Todd.  You mention m4, yet the output you show
> is around flex?  
> 
> I can update our documentation, but need more details and confirmation
> by the respective GCC maintainers on what exactly to adjust.
> 

Gerald, thanks for the reply. When it fell over, I dug into the config.log file and was able to determine that it was a bad m4 macro. I can try to re-produce it to get you more details, but it may take me a while to get to it. Do you want me to do this?

Thanks,
Todd

Re: m4 requirement

[DJ Delorie]

I think I've seen this one, it's something like this: GNU flex calls M4
when you run flex.  GMP disables M4 and runs flex; flex then tries to
run m4-not-used (or whatever it's called) instead of m4.