diff --git a/configure.in b/configure.in
index 3d55d71f..00ba1656 100644
--- a/configure.in
+++ b/configure.in
@@ -20,7 +20,7 @@ AC_CHECK_LIB(uca, __uc_get_grs)
 dnl Checks for header files.
 AC_HEADER_STDC
 AC_CHECK_HEADERS(asm/ptrace_offsets.h endian.h execinfo.h ia64intrin.h \
-		 sys/uc_access.h unistd.h)
+		 sys/uc_access.h unistd.h signal.h)
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
@@ -28,7 +28,19 @@ AC_C_INLINE
 AC_TYPE_SIGNAL
 AC_TYPE_SIZE_T
 
-AC_CHECK_TYPES([sighandler_t])
+CPPFLAGS="${CPPFLAGS} -D_GNU_SOURCE"
+if test x$enable_debug = xyes; then
+  CPPFLAGS="${CPPFLAGS} -DDEBUG"
+else
+  CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+fi
+
+AC_CHECK_TYPES([sighandler_t], [], [],
+[$ac_includes_default
+#if HAVE_SIGNAL_H
+# include <signal.h>
+#endif
+])
 
 dnl Checks for library functions.
 AC_FUNC_MEMCMP
@@ -65,13 +77,6 @@ AC_ARG_ENABLE(debug,
 
 LIBUNWIND___THREAD
 
-CPPFLAGS="${CPPFLAGS} -D_GNU_SOURCE"
-if test x$enable_debug = xyes; then
-  CPPFLAGS="${CPPFLAGS} -DDEBUG"
-else
-  CPPFLAGS="${CPPFLAGS} -DNDEBUG"
-fi
-
 if test x$GCC = xyes; then
   CFLAGS="${CFLAGS} -Wall -Wsign-compare"
 fi