elisp.eclass: Depend on virtual/emacs on the build system.

For byte-compilation, Emacs is required to run on the native
build system. Therefore BDEPEND on virtual/emacs in EAPI 7.

Reorganise EAPI conditionals to be more compact.

eclass/elisp.eclass

@@ -65,24 +65,24 @@
 # files by dodoc in src_install().
 
 inherit elisp-common
+case ${EAPI:-0} in
+	0|1|2|3|4|5) inherit epatch ;;
+	6|7) ;;
+	*) die "${ECLASS}: EAPI ${EAPI} not supported" ;;
+esac
 
 case ${EAPI:-0} in
-	0|1)
-		inherit epatch
-		EXPORT_FUNCTIONS src_{unpack,compile,install} \
-			pkg_{setup,postinst,postrm} ;;
-	2|3|4|5)
-		inherit epatch
-		EXPORT_FUNCTIONS src_{unpack,prepare,configure,compile,install} \
+	0|1) EXPORT_FUNCTIONS src_{unpack,compile,install} \
 			pkg_{setup,postinst,postrm} ;;
-	6|7)
-		EXPORT_FUNCTIONS src_{unpack,prepare,configure,compile,install} \
+	*) EXPORT_FUNCTIONS src_{unpack,prepare,configure,compile,install} \
 			pkg_{setup,postinst,postrm} ;;
-	*) die "${ECLASS}: EAPI ${EAPI} not supported" ;;
 esac
 
-DEPEND=">=virtual/emacs-${NEED_EMACS:-23}"
-RDEPEND="${DEPEND}"
+RDEPEND=">=virtual/emacs-${NEED_EMACS:-23}"
+case ${EAPI:-0} in
+	0|1|2|3|4|5|6) DEPEND="${RDEPEND}" ;;
+	*) BDEPEND="${RDEPEND}" ;;
+esac
 
 # @FUNCTION: elisp_pkg_setup
 # @DESCRIPTION: