x11-misc/xkeycaps: 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.

Closes: https://bugs.gentoo.org/871129
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

x11-misc/xkeycaps/xkeycaps-2.47_p7.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
@@ -23,10 +23,12 @@ RDEPEND="
 	x11-libs/libXt
 	x11-misc/xbitmaps
 "
-DEPEND="${RDEPEND}"
-BDEPEND="
-	>=sys-apps/sed-4
+DEPEND="
+	${RDEPEND}
 	x11-base/xorg-proto
+"
+BDEPEND="
+	sys-devel/gcc
 	>=x11-misc/imake-1.0.8-r1
 "
 
@@ -47,7 +49,7 @@ src_prepare() {
 
 src_configure() {
 	CC="$(tc-getBUILD_CC)" LD="$(tc-getLD)" \
-		IMAKECPP="${IMAKECPP:-$(tc-getCPP)}" xmkmf || die
+		IMAKECPP="${IMAKECPP:-${CHOST}-gcc -E}" xmkmf || die
 	sed -i \
 		-e "s,all:: xkeycaps.\$(MANSUFFIX).html,all:: ,g" \
 		Makefile || die