Fix broken build on AIX 7.2

Without this fix, the build on AIX 7.2 with xlc fails in the ‘CCLD
temacs’ step with the diagnostic ‘ld: 0711-317 ERROR: Undefined
symbol: BC’.  This is because -lcurses does not define BC etc.
* configure.ac: When building terminfo.o, define
TERMINFO_DEFINES_BC if the library defines BC etc.
* src/terminfo.c (UP, BC, PC): Define depending on
TERMINFO_DEFINES_BC, not on TERMINFO.

(cherry picked from commit 632917461a7c1893a83979a3873b51d4da3b8a42)

1 files changed, 3 insertions, 3 deletions

diff --git a/src/terminfo.c b/src/terminfo.c
index 15aff317f15..a9c9572bbb2 100644
--- a/src/terminfo.c
+++ b/src/terminfo.c
@@ -23,10 +23,10 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 /* Define these variables that serve as global parameters to termcap,
    so that we do not need to conditionalize the places in Emacs
-   that set them.  But don't do that for terminfo, as that could
-   cause link errors when using -fno-common.  */
+   that set them.  But don't do that if terminfo defines them, as that
+   could cause link errors when using -fno-common.  */
 
-#if !TERMINFO
+#ifndef TERMINFO_DEFINES_BC
 char *UP, *BC, PC;
 #endif