Fix GCOV not working for PHP-7.4 and master branches

Code coverage reports (`make lcov`), since commit eef8522 (7.4 branch),
generates incorrect coverage and emits warnings. Simplifying the
Makefile.gcov file has the side-effect of resolving the issue.

    Processing sapi/cli/php_http_parser.gcda
    php-src/lcov_data/sapi/cli/php_http_parser.gcda:stamp mismatch with notes file
    geninfo: WARNING: gcov did not create any files for php-src/lcov_data/sapi/cli/php_http_parser.gcda!
    ...
    Processing ext/mbstring/mb_gpc.gcda
    php-src/lcov_data/ext/mbstring/mb_gpc.gcda:stamp mismatch with notes file
    geninfo: WARNING: gcov did not create any files for php-src/lcov_data/ext/mbstring/mb_gpc.gcda!

Closes: https://bugs.php.net/bug.php?id=52718.
See also: https://bugs.php.net/bug.php?id=78288.

.gitignore

@@ -249,7 +249,6 @@ tmp-php.ini
 # ------------------------------------------------------------------------------
 *.gcda
 *.gcno
-/lcov_data/
 /lcov_html/
 /php_lcov.info
 

build/Makefile.gcov

@@ -2,76 +2,33 @@
 # LCOV
 #
 
-LCOV_INCLUDE="."
-
 lcov: lcov-html
 
 lcov-test: lcov-clean-data test
 
 php_lcov.info: lcov-test
-	@echo "Generating data for $@"
-	@rm -rf lcov_data/
-	@$(mkinstalldirs) lcov_data/
-	@echo
-	-@files=`find . -name \*.gcda -o -name \*.gcno -o -name \*.da -o -name \*.c -o -name \*.h | sed -e 's/^\.\///' | sed -e 's/\.gcda//g' -e 's/\.gcno//g' -e 's/\.da//g' | $(EGREP) $(LCOV_INCLUDE) | sed -e 's/.libs/zzzz/g' | sort | sed -e 's/zzzz/.libs/g' | uniq` ;\
-	for x in $$files; do \
-		echo -n . ;\
-		y=`echo $$x | sed -e 's!\.libs/!!'`; \
-		dir=lcov_data/`dirname $$x`; \
-		test -d "$$dir" || $(mkinstalldirs) "$$dir"; \
-		if test -f "$(top_srcdir)/$$y.c"; then \
-			ln -f -s $(top_srcdir)/$$y.c lcov_data/$$y.c; \
-		fi; \
-		if test -f "$(top_srcdir)/$$y.h"; then \
-			ln -f -s $(top_srcdir)/$$y.h lcov_data/$$y.h; \
-		fi; \
-		if test -f "$(top_srcdir)/$$y.re"; then \
-			ln -f -s $(top_srcdir)/$$y.re lcov_data/$$y.re; \
-		fi; \
-		if test -f "$(top_srcdir)/$$y.y"; then \
-		        ln -f -s $(top_srcdir)/$$y.y lcov_data/$$y.y; \
-		fi; \
-		if test -f "$(top_srcdir)/$$y.l"; then \
-		        ln -f -s $(top_srcdir)/$$y.l lcov_data/$$y.l; \
-		fi; \
-		if test -f "$(top_srcdir)/$$y"; then \
-		        ln -f -s $(top_srcdir)/$$y lcov_data/$$y; \
-		fi; \
-		if test -f "$(top_builddir)/$$y.c"; then \
-			ln -f -s $(top_builddir)/$$y.c lcov_data/$$y.c; \
-		fi; \
-		if test -f "$$x.gcno"; then \
-			cp $$x.gcno lcov_data/$$y.gcno ; \
-		fi; \
-		if test -f "$$x.gcda"; then \
-			cp $$x.gcda lcov_data/$$y.gcda ; \
-		fi; \
-		if test -f "$$x.da"; then \
-			cp $$x.da   lcov_data/$$y.da ; \
-		fi; \
-		if test -f "$$x.bb"; then \
-			cp $$x.bb   lcov_data/$$y.bb ; \
-		fi; \
-		if test -f "$$x.bbg"; then \
-			cp $$x.bbg  lcov_data/$$y.bbg ; \
-		fi; \
-	done; \
-	for dir in ext/date/lib ext/fileinfo/libmagic ext/gd/libgd ext/pcre/pcre2lib; do \
-		if test -d lcov_data/$$dir; then \
-			rm -rf lcov_data/$$dir ; \
-		fi; \
-	done
-	@echo
-	@echo "Generating $@"
-	@$(LTP) --directory lcov_data/ --capture --base-directory=lcov_data --output-file $@
+	@echo "Generating lcov data for $@"
+	@$(LTP) --capture --no-external --directory . --output-file $@
+	@echo "Stripping bundled libraries from $@"
+	@$(LTP) --remove $@ \
+		'*/<stdout>' \
+		'$(top_srcdir)/ext/bcmath/libbcmath/*' \
+		'$(top_srcdir)/ext/date/lib/*' \
+		'$(top_srcdir)/ext/fileinfo/libmagic/*' \
+		'$(top_srcdir)/ext/gd/libgd/*' \
+		'$(top_srcdir)/ext/hash/sha3/*' \
+		'$(top_srcdir)/ext/mbstring/libmbfl/*' \
+		'$(top_srcdir)/ext/opcache/jit/libudis86/*' \
+		'$(top_srcdir)/ext/pcre/pcre2lib/*' \
+		'$(top_srcdir)/ext/xmlrpc/libxmlrpc/*' \
+		--output-file $@
 
 lcov-html: php_lcov.info
 	@echo "Generating lcov HTML"
 	@$(LTP_GENHTML) --legend --output-directory lcov_html/ --title "PHP Code Coverage" php_lcov.info
 
 lcov-clean:
 	rm -f php_lcov.info
-	rm -rf lcov_data/
 	rm -rf lcov_html/
 
 lcov-clean-data: