x11-terms/tilda: fix build (popen), bashism, is X11 program

expose popen() w/ _POSIX_C_SOURCE
can't switch to -std=gnu99 since autoconf appends -std=c99 last, unless
enable-clang is used, which is not the case
gdkx.h is required unconditionally, so gtk+[X]
fix bashism in configure.ac

Closes: https://bugs.gentoo.org/927874
Closes: https://bugs.gentoo.org/958049
Closes: https://bugs.gentoo.org/972749
Signed-off-by: Nicolas PARLANT <nicolas.parlant@parhuet.fr>
Part-of: https://codeberg.org/gentoo/gentoo/pulls/647
Merges: https://codeberg.org/gentoo/gentoo/pulls/647
Signed-off-by: Sam James <sam@gentoo.org>

x11-terms/tilda/files/tilda-2.0.0-fix_bashism.patch

@@ -0,0 +1,14 @@
+see PR pending https://github.com/lanoxx/tilda/pull/545.patch
+see also https://bugs.gentoo.org/927874
+remove bashism
+--- a/configure.ac
++++ b/configure.ac
+@@ -186,7 +186,7 @@ cflagcount=0
+ for flag in ${CFLAGS}; do
+     cflaglines=$cflaglines$flag" "
+     cflagcount=$(($cflagcount+1))
+-    if (( $cflagcount % 4 == 0)); then
++    if test $((cflagcount % 4)) -eq 0; then
+        dnl Here we concatenate the current cflaglines variable with a newline and enough spaces
+        dnl such that the lines are correctly indented. Do not try to indent or reformat the
+        dnl position of the double quotes (\").

x11-terms/tilda/tilda-2.0.0.ebuild

@@ -1,4 +1,4 @@
-# Copyright 1999-2025 Gentoo Authors
+# Copyright 1999-2026 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=8
@@ -19,14 +19,21 @@ RDEPEND="x11-libs/vte:2.91
 	>=dev-libs/glib-2.8.4:2
 	dev-libs/confuse:=
 	gnome-base/libglade
-	x11-libs/gtk+:3
-	x11-libs/libX11"
+	x11-libs/gtk+:3[X]
+	x11-libs/libX11
+"
 DEPEND="${RDEPEND}"
 BDEPEND="virtual/pkgconfig
 	sys-devel/gettext"
 
+PATCHES=(
+	"${FILESDIR}"/${PN}-2.0.0-fix_bashism.patch
+)
+
 src_prepare() {
 	default
-	append-cflags -std=c99
+	# 972749 expose popen()
+	# see also https://github.com/lanoxx/tilda/issues/522
+	append-cppflags -D_POSIX_C_SOURCE
 	eautoreconf
 }