On 06/13/2010 02:16 PM, Rainer Jung wrote: > On 13.06.2010 13:29, Ruediger Pluem wrote: >> >> >> On 06/12/2010 09:07 PM, Stefan Fritsch wrote: >>> On Friday 11 June 2010, Ruediger Pluem wrote: >>>>> Modified: httpd/httpd/trunk/configure.in >>>>> URL: >>>>> http://svn.apache.org/viewvc/httpd/httpd/trunk/configure.in?rev= >>>>> 951893&r1=951892&r2=951893&view=diff >>>>> ================================================================ >>>>> ============== --- httpd/httpd/trunk/configure.in (original) >>>>> +++ httpd/httpd/trunk/configure.in Sun Jun 6 16:54:51 2010 >>>>> @@ -170,6 +170,9 @@ dnl PCRE and for our config tests will b >>>>> >>>>> AC_PROG_CC >>>>> AC_PROG_CPP >>>>> >>>>> >>>>> +dnl Try to get c99 support for variadic macros >>>>> +AC_PROG_CC_C99 >>>>> + >>>> This test is only present since autoconf>= 2.60. >>>> Since 2.59 is still delivered with RedHat 4 / 5 this does not work >>>> there, but the error is non fatal. >>> >>> This means it is not a good idea to run buildconf on RH4/5, but a >>> configure created somewhere else with autoconf 2.60 should work fine. >>> So this mainly affects httpd developers. >>> >>> We can either bump AC_PREREQ to 2.60, making it impossible to run >>> buildconf on RH4/5, or we can include the code for AC_PROG_CC_C99 >>> (about 200 lines) from autoconf 2.60 in httpd's build system. The >>> current state seems like a bad idea, because of the potential to ship >>> a broken configure in release tarballs. >>> >>> Preferences? Is anyone here developing on RHEL? >> >> I do so partly. This is why I came across this :-). What does >> AC_PROG_CC_C99 >> really do? Not that I am suggesting to remove this call from configure.in >> but what does it do? Does it change compiler parameters such that the >> compiler >> is switched into C99 mode? If yes isn't gcc by default? >> So if this is true my idea would be if it would be possible to just call >> AC_PROG_CC_C99 if autoconf is>= 2.60. > > I'm jumping in here: > > -- Macro: AC_PROG_CC_C99 > If the C compiler is not in C99 mode by default, try to add an > option to output variable `CC' to make it so. This macro tries > various options that select C99 on some system or another, > preferring extended functionality modes over strict conformance > modes. It considers the compiler to be in C99 mode if it handles > `_Bool', `//' comments, flexible array members, `inline', signed > and unsigned `long long int', mixed code and declarations, named > initialization of structs, `restrict', `va_copy', varargs macros, > variable declarations in `for' loops, and variable length arrays. > > After calling this macro you can check whether the C compiler has > been set to accept C99; if not, the shell variable > `ac_cv_prog_cc_c99' is set to `no'. > > More concrete it tries to compile a c99 program using the given CC and > optionally with the flags -std=gnu99 -std=c99 -c99 -AC99 -xc99=all > -qlanglvl=extc99 until it eventually works. Then it adds the needed flag > to CC. > > I'm using gcc 4.1.2 and there the macro adds -std=gnu99 to CC in > build/config_vars.mk. > > Stefan: The discussion thread I cited also contains the info how to use > the directive only if it exists: > > ifdef([AC_PROG_CC_C99], [AC_PROG_CC_C99])
+1 to this solution. -0.5 on importing the code for AC_PROG_CC_C99 in configure.in Regards Rüdiger
