[RPL/2] Autoconf error in finding libm

[Jonathan Busby]

I have been racking my brain over what is causing this problem, but so far,
I haven't figured out what the core cause is. When I pass "--enable-rplcas"
to configure in 4.1.29 the configure script fails with "configure: error:
Can not find libm !" . If I change configure.ac to use "AC_SEARCH_LIBS
(exp, m , , AC_MSG_ERROR([Can not find libm !]))" and I comment out the
AC_CHECK_LIB line, then the configure script finds libm, but, later in the
configure script, when the configure scripts for some of the tools are
being executed, I get the same error. After  examining the autotools
scripts, it seems that there is an error in the call to AC_CHECK_LIB for
libm as main is not an exported function of libm, but, substituting
something like "exp" still doesn't clear up the problem. Just to make sure
that my system configuration wasn't the cause, I made a tiny test
configure.ac and ran autoconf :

"
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking for exp  in -lm... yes
configure: creating ./config.status
"

The test configure.ac is just :

"
AC_INIT([test],[0.01])
AC_CHECK_LIB(m, exp , , AC_MSG_ERROR([Can not find libm !]))
AC_OUTPUT
"

As you can see it finds libm, but, if I tell it to look for main in libm,
it fails.

Do you know what the problem might be?

Thanks,

Jonathan
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