With ncurses-6.0-20170701.patch

       + improve compatibility between different configurations of new_prescr,
         fixing a case with threaded code and term-driver where c++/demo did
         not work (cf: 20160213).

the pthread_self(3) function call had been called without checking if the
library libpthread has been linked.  This break e.g. grub (boo#1058509) if
statically linked.

---
 ncurses/tinfo/lib_setup.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- ncurses/tinfo/lib_setup.c
+++ ncurses/tinfo/lib_setup.c	2018-03-01 10:58:23.280319133 +0000
@@ -830,8 +830,9 @@ _nc_find_prescr(void)
 {
     SCREEN *result = 0;
     PRESCREEN_LIST *p;
+    pthread_t id = ((pthread_self)) ? pthread_self() : (pthread_t)getpid();
     for (p = _nc_prescreen.allocated; p != 0; p = p->next) {
-	if (p->id == pthread_self()) {
+	if (p->id == id) {
 	    result = p->sp;
 	    break;
 	}
@@ -848,8 +849,9 @@ NCURSES_EXPORT(void)
 _nc_forget_prescr(void)
 {
     PRESCREEN_LIST *p, *q;
+    pthread_t id = ((pthread_self)) ? pthread_self() : (pthread_t)getpid();
     for (p = _nc_prescreen.allocated, q = 0; p != 0; q = p, p = p->next) {
-	if (p->id == pthread_self()) {
+	if (p->id == id) {
 	    if (q) {
 		q->next = p->next;
 	    } else {
@@ -885,7 +887,7 @@ new_prescr(void)
 #ifdef USE_PTHREADS
 	    PRESCREEN_LIST *p = typeCalloc(PRESCREEN_LIST, 1);
 	    if (p != 0) {
-		p->id = pthread_self();
+		p->id = ((pthread_self)) ? pthread_self() : (pthread_t)getpid();
 		p->sp = sp;
 		p->next = _nc_prescreen.allocated;
 		_nc_prescreen.allocated = p;