Qs: -pthread, make builds warns be errors, etc

[Matt England]

Hello,

I'm building my first autoconf scripts (reference to my scripts at end of 
email) and have these questions for which I have yet to find in the 
docs.  Could the autoconf community provide any help?  Many thanks in advance.


* Portable threads compiler flag?

In my pre-autoconf Makefiles I'm using -pthread compiler flag (g++) on 
Linux systems and -mthreads on Windows-MinGW systems.  Can I address this 
with autoconf control, and if so, how?  Is it best to use a 
AC_CANONICAL_HOST-based conditional?

Also, what other "thread" C++ (namely g++) flags are used on other systesm 
(besides my current Windows and Linux builds)?


* Make compile/link-time warnings stop the ./configure execution?

I am experiencing warnings like this in my config.log:

configure:2123: g++ -o conftest -g -O2   -lxerces-c -lssl -lpqxx 
conftest.cc  >&5
/usr/bin/ld: warning: libstdc++.so.6, needed by 
/usr/lib/gcc-lib/i486-linux/3.3.5/../../../libpqxx.so, may conflict with 
libstdc++.so.5
/usr/bin/ld: warning: libssl.so.0.9.8, needed by 
/usr/bin/../lib/libpq.so.4, may conflict with libssl.so.0.9.7

If I decide to do so, can I make the ./configure (via configure.ac) stop 
its execution in the event of warnings?   I'm looking for an analogy to 
'g++ -Werror'.


* How can I determine diff Linux systems?

Is there any way I can distinguish between different Linux system flavors 
with AC_CANONICAL_HOST ?  Last I checked, they all said "Linux".

The only portable way I know how to do this in my Makefiles is to look at 
the content of /etc/issue and hope that a human didn't change said file's 
content.


* Is the autom4te.cache generation (on my autoconf-2.59 system) optional?

I'm trying to minimize the file clutter that autoconf generates in my 
developers working filesystem areas (eg, 'svn status' looks messier then 
need be after running ./configure).  Is autom4te.cache directory needed, 
and if not, is there a way I can eliminate it's creation in the 
configure.ac script?  Is it fair to say that this autom4te.cache dir isn't 
used/read by a human  (something that one can not also say for config.log) 
and therefore could be made optional?


* When will latest autoconf docs generate html pages?

The current autoconf manual flavor doesn't come in html flavor; any idea 
when it will?  Until then, I continually use the latest html doc I can find:
<http://www.gnu.org/software/autoconf/manual/autoconf-2.57/>.  Does a 
better flavor exist?


For reference...

My autoconf scripts (which are mostly designed to test for availability of 
third-party libraries on the build system):

* http://svn.cleversafe.org/dscore/trunk/configure.ac
* 
http://svn.cleversafe.org/dscore/trunk/common/misc/scripts-autoconf/configure.ac.core

I'm still not using this stuff in my official build/Makefile process, but 
I'm getting pretty close.


-Matt