xterm: Add _GNU_SOURCE via CFLAGS

This ensures that definitions of functions e.g. ptsname and wcwidth are
added correctly.

Fixes
| ./main.c:2940:8: error: incompatible integer to pointer conversion initializing 'char *' with an expression of type 'int' [-Wint-conversion]
|         char *name = ptsname(*pty);
|               ^      ~~~~~~~~~~~~~

| ./util.c:5506:19: error: use of undeclared identifier 'wcwidth'
|             my_wcwidth = wcwidth;
|                          ^

Signed-off-by: Khem Raj <raj.khem@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/meta-oe/recipes-graphics/xorg-app/xterm_373.bb b/meta-oe/recipes-graphics/xorg-app/xterm_373.bb
index 7e36f475c..bc555cbcd 100644
--- a/meta-oe/recipes-graphics/xorg-app/xterm_373.bb
+++ b/meta-oe/recipes-graphics/xorg-app/xterm_373.bb
@@ -27,6 +27,8 @@ EXTRA_OECONF = " --x-includes=${STAGING_INCDIR} \
 
 B = "${S}"
 
+CFLAGS += "-D_GNU_SOURCE"
+
 do_configure() {
     gnu-configize --force
     sed -e "s%/usr/contrib/X11R6%${STAGING_LIBDIR}%g" -i configure