media-fonts/x11fonts-jmk: 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/870784
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

media-fonts/x11fonts-jmk/x11fonts-jmk-3.0-r4.ebuild

@@ -17,6 +17,7 @@ SLOT="0"
 KEYWORDS="~alpha amd64 arm ~ia64 ~loong ppc ~s390 sparc x86"
 
 BDEPEND="
+	sys-devel/gcc
 	>=x11-misc/imake-1.0.8-r1
 	>=x11-apps/mkfontscale-1.2.0
 	x11-apps/bdftopcf"
@@ -27,7 +28,7 @@ PATCHES=(
 
 src_configure() {
 	CC="$(tc-getBUILD_CC)" LD="$(tc-getLD)" \
-		IMAKECPP="${IMAKECPP:-$(tc-getCPP)}" xmkmf || die
+		IMAKECPP="${IMAKECPP:-${CHOST}-gcc -E}" xmkmf || die
 }
 
 src_install() {