net-misc/graftcp: pass $(CC) when make install

The makefile call $(CC) to detect the machine architecture in a variable
thus it will be evaluated each time we enter the makefile, even when
executing `make install`

Signed-off-by: Yuhang Zeng <unlsycn@unlsycn.com>

net-misc/graftcp/graftcp-0.7.1.ebuild

@@ -53,6 +53,6 @@ src_compile() {
 }
 
 src_install() {
-	emake DESTDIR="${D}" PREFIX="/usr" install
+	emake CC="$(tc-getCC)" CXX="$(tc-getCXX)" AR="$(tc-getAR)" DESTDIR="${D}" PREFIX="/usr" install
 	use systemd && emake DESTDIR="${D}" PREFIX="/usr" install_systemd
 }