Remove long-dead support for platforms without sig_atomic_t.

C89 requires <signal.h> to define sig_atomic_t, and there is no evidence
in the buildfarm that any supported platforms don't comply.  Remove the
configure test to stop wasting build cycles on a purely historical issue.
(Once upon a time, we cared about supporting C89-compliant compilers on
machines with pre-C89 system headers, but that use-case has been dead for
quite a few years.)

I have some other fixes planned in this area, but let's start with this
to see if the buildfarm produces any surprising results.

1 files changed, 0 insertions, 14 deletions

diff --git a/configure b/configure
index 0bed81c2e4a..0376a7ca919 100755
--- a/configure
+++ b/configure
@@ -14151,20 +14151,6 @@ _ACEOF
 fi
 
 
-# We also check for sig_atomic_t, which *should* be defined per ANSI
-# C, but is missing on some old platforms.
-ac_fn_c_check_type "$LINENO" "sig_atomic_t" "ac_cv_type_sig_atomic_t" "#include <signal.h>
-"
-if test "x$ac_cv_type_sig_atomic_t" = xyes; then :
-
-cat >>confdefs.h <<_ACEOF
-#define HAVE_SIG_ATOMIC_T 1
-_ACEOF
-
-
-fi
-
-
 # Check for extensions offering the integer scalar type __int128.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __int128" >&5
 $as_echo_n "checking for __int128... " >&6; }