ucontext.h check requires signal.h.
diff --git a/configure b/configure
index 114f2fd..3cda30d 100755
--- a/configure
+++ b/configure
@@ -11541,7 +11541,6 @@
-
for ac_header in \
arpa/inet.h \
arpa/nameser.h \
@@ -11608,7 +11607,6 @@
sys/wait.h \
syscall.h \
termios.h \
- ucontext.h \
unistd.h \
utime.h \
@@ -11990,6 +11988,54 @@
+for ac_header in ucontext.h
+do
+as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
+echo "$as_me:$LINENO: checking for $ac_header" >&5
+echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
+if eval "test \"\${$as_ac_Header+set}\" = set"; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ cat >conftest.$ac_ext <<_ACEOF
+#line $LINENO "configure"
+#include "confdefs.h"
+#include <signal.h>
+
+#include <$ac_header>
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+ (eval $ac_compile) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } &&
+ { ac_try='test -s conftest.$ac_objext'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; }; then
+ eval "$as_ac_Header=yes"
+else
+ echo "$as_me: failed program was:" >&5
+cat conftest.$ac_ext >&5
+eval "$as_ac_Header=no"
+fi
+rm -f conftest.$ac_objext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
+if test `eval echo '${'$as_ac_Header'}'` = yes; then
+ cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_header" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+
+done
+
+
+
echo "$as_me:$LINENO: checking for an ANSI C-conforming const" >&5
echo $ECHO_N "checking for an ANSI C-conforming const... $ECHO_C" >&6
if test "${ac_cv_c_const+set}" = set; then
