x11-terms/kterm: force gcc -E for imake's generation

Requires traditional cpp support and is broken in all sort of ways
with clang-cpp / -E. Can still use clang & friends for everything else.

Ideally these packages need to be built another way or last rited,
imake will just accumulate more problems.

wrt #873631, this only helps a bit and still has several clang issues.

Bug: https://bugs.gentoo.org/873631
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

x11-terms/kterm/kterm-6.2.0-r7.ebuild

@@ -1,4 +1,4 @@
-# Copyright 1999-2021 Gentoo Authors
+# Copyright 1999-2022 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=7
@@ -28,6 +28,7 @@ RDEPEND="
 	!<games-board/xscrabble-2.10-r4"
 DEPEND="${RDEPEND}"
 BDEPEND="
+	sys-devel/gcc
 	virtual/pkgconfig
 	x11-misc/gccmakedep
 	>=x11-misc/imake-1.0.8-r1"
@@ -48,7 +49,7 @@ src_prepare() {
 
 src_configure() {
 	CC="$(tc-getBUILD_CC)" LD="$(tc-getLD)" \
-		IMAKECPP="${IMAKECPP:-$(tc-getCPP)}" xmkmf -a || die
+		IMAKECPP="${IMAKECPP:-${CHOST}-gcc -E}" xmkmf -a || die
 }
 
 src_compile() {