This fixes these autoconf warnings:

Running aclocal-1.11...
configure.in:195: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
../../lib/autoconf/lang.m4:194: AC_LANG_CONFTEST is expanded from...
../../lib/autoconf/general.m4:2591: _AC_COMPILE_IFELSE is expanded from...
../../lib/autoconf/general.m4:2607: AC_COMPILE_IFELSE is expanded from...
configure.in:140: VTE_CC_TRY_FLAG is expanded from...
../../lib/m4sugar/m4sh.m4:606: AS_IF is expanded from...
../../lib/autoconf/general.m4:2032: AC_CACHE_VAL is expanded from...
../../lib/autoconf/general.m4:2053: AC_CACHE_CHECK is expanded from...
configure.in:195: the top level
[etc]

Should also fix detection of non-support for -fno-common in sun cc,
https://bugzilla.gnome.org/show_bug.cgi?id=616001 .
(cherry picked from commit e2266006)