Ensure that MAIN_FIRST have finished compilation before doing the rest

* lisp/Makefile.in (main-first): Ensure that we're done with the
main bits before starting on the rest.
(GREP_OPTIONS): Depend on main-first.
(MAIN_FIRST): Compile cconv.el before c-by.el (bug#8764).

lisp/Makefile.in

@@ -98,7 +98,7 @@ COMPILE_FIRST += $(lisp)/emacs-lisp/autoload.elc
 
 # Files to compile early in compile-main.  Works around bug#25556.
 MAIN_FIRST = ./emacs-lisp/eieio.el ./emacs-lisp/eieio-base.el \
-  ./cedet/semantic/db.el
+  ./cedet/semantic/db.el ./emacs-lisp/cconv.el
 
 # Prevent any settings in the user environment causing problems.
 unexport EMACSDATA EMACSDOC EMACSPATH
@@ -338,10 +338,10 @@ endif
 
 # Compile all the Elisp files that need it.  Beware: it approximates
 # 'no-byte-compile', so watch out for false-positives!
-compile-main: gen-lisp compile-clean
+compile-main: gen-lisp compile-clean main-first
 	@(cd $(lisp) && 			     \
 	els=`echo "${SUBDIRS_REL} " | sed -e 's|/\./|/|g' -e 's|/\. | |g' -e 's| |/*.el |g'`; \
-	for el in ${MAIN_FIRST} $$els; do            \
+	for el in $$els; do            \
 	  test -f $$el || continue; 		     \
 	  test ! -f $${el}c && 			     \
 	      GREP_OPTIONS= grep '^;.*[^a-zA-Z]no-byte-compile: *t' $$el > /dev/null && \
@@ -354,6 +354,18 @@ compile-main: gen-lisp compile-clean
 		  TARGETS="$$chunk";		     \
 	done
 
+# Compile some important files first.
+main-first:
+	@(cd $(lisp) && 			     \
+	for el in ${MAIN_FIRST}; do                  \
+	  echo "$${el}c";                            \
+	done | xargs $(XARGS_LIMIT) echo) |	     \
+	while read chunk; do			     \
+	  $(MAKE) compile-targets		     \
+		  NATIVE_DISABLED=$(NATIVE_SKIP_NONDUMP) \
+		  TARGETS="$$chunk";		     \
+	done
+
 .PHONY: compile-clean
 # Erase left-over .elc files that do not have a corresponding .el file.
 compile-clean: