community/dvdauthor: use .pc to detect libxml

for some reason, the other detection utilising m4 has m4 allocate in a loop until oom

community/dvdauthor/APKBUILD

@@ -2,7 +2,7 @@
 # Maintainer: Francesco Colista <fcolista@alpinelinux.org>
 pkgname=dvdauthor
 pkgver=0.7.2
-pkgrel=8
+pkgrel=9
 pkgdesc="DVD authoring tools"
 url="https://dvdauthor.sourceforge.net/"
 arch="all"
@@ -20,6 +20,7 @@ makedepends="
 	"
 subpackages="$pkgname-doc"
 source="https://downloads.sourceforge.net/$pkgname/$pkgname-$pkgver.tar.gz
+	libxml-pc.patch
 	pkgconfig-1.patch
 	"
 builddir="$srcdir/$pkgname"
@@ -48,5 +49,6 @@ package() {
 
 sha512sums="
 202b8bba38939d122dc864921a57e89906ca99ddabf44e3b07419cc42cc052567cd892b41f1171c9c195c9a770758e9319a942ea64d14ee8fa847588c7761125  dvdauthor-0.7.2.tar.gz
+47e6141afa6321c12b73dbedcef6b1ccd6274528af3fc9bddf85fc7f43b9673b8db93f1341c3c9b205d19468b93f38847189fc04fa433848936558de3b0306c8  libxml-pc.patch
 3dd640f1569d4d99c1ef67f8515c06b04bf9b23e6aa98ca7642735a8e01d22fed507b328c7c6a9b7797e1e76e827fd4da59fec214eba57b9595dfba2e619dc8c  pkgconfig-1.patch
 "

community/dvdauthor/libxml-pc.patch

@@ -0,0 +1,77 @@
+From 45705ece5ec5d7d6b9ab3e7a68194796a398e855 Mon Sep 17 00:00:00 2001
+From: Hugh McMaster <hugh.mcmaster@outlook.com>
+Date: Wed, 26 Feb 2020 23:44:23 +1100
+Subject: [PATCH] Use PKG_CHECK_MODULES to detect the libxml2 library
+
+---
+ configure.ac    | 8 +++-----
+ src/Makefile.am | 8 ++++----
+ 2 files changed, 7 insertions(+), 9 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index f4b270f..f4e1715 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -8,6 +8,8 @@ LT_INIT
+ 
+ AC_PROG_INSTALL
+ 
++PKG_PROG_PKG_CONFIG
++
+ AC_SYS_LARGEFILE
+ 
+ AC_HEADER_STDBOOL
+@@ -100,6 +102,7 @@ else
+     AC_MSG_ERROR([freetype not found])
+ fi
+ 
++PKG_CHECK_MODULES([XML2], [libxml-2.0 >= 2.6.0])
+ 
+ AC_ARG_ENABLE([default-video-format],
+ AS_HELP_STRING([--enable-default-video-format=format], [specify a default video format, either NTSC or PAL, to be used if no configuration or input setting is given]),
+@@ -135,11 +138,6 @@ dnl AM_LANGINFO_CODESET
+ 
+ AM_ICONV
+ 
+-ifdef([AM_PATH_XML2],
+-    [AM_PATH_XML2(2.6.0, , AC_MSG_ERROR([You must have libxml2 >= 2.6.0 installed]))],
+-    [errprint([You must have libxml2 (>= 2.6.0) installed
+-])m4_exit(1)AC_MSG_ERROR([You must have libxml2 (>= 2.6.0) installed])])
+-
+ AC_CHECK_DECLS(O_BINARY, , , [ #include <fcntl.h> ] )
+ 
+ AC_OUTPUT(Makefile doc/Makefile src/Makefile)
+diff --git a/src/Makefile.am b/src/Makefile.am
+index c7f89a9..37b3fd1 100644
+--- a/src/Makefile.am
++++ b/src/Makefile.am
+@@ -8,7 +8,7 @@ endif
+ nodist_bin_SCRIPTS = dvddirdel
+ 
+ AM_CPPFLAGS = -DSYSCONFDIR="\"$(sysconfdir)\"" \
+-    @XML_CPPFLAGS@ @MAGICK_CPPFLAGS@ @FREETYPE_CPPFLAGS@ @FRIBIDI_CFLAGS@ @FONTCONFIG_CFLAGS@
++    @XML2_CFLAGS@ @MAGICK_CPPFLAGS@ @FREETYPE_CPPFLAGS@ @FRIBIDI_CFLAGS@ @FONTCONFIG_CFLAGS@
+ AM_CFLAGS = -Wall
+ 
+ dvdauthor_SOURCES = dvdauthor.c common.h dvdauthor.h da-internal.h \
+@@ -16,17 +16,17 @@ dvdauthor_SOURCES = dvdauthor.c common.h dvdauthor.h da-internal.h \
+     dvdifo.c dvdvob.c dvdpgc.c \
+     dvdcli.c readxml.c readxml.h \
+     conffile.c conffile.h compat.c compat.h rgb.h
+-dvdauthor_LDADD = $(LIBICONV) $(XML_LIBS)
++dvdauthor_LDADD = $(LIBICONV) $(XML2_LIBS)
+ 
+ dvdunauthor_SOURCES = dvdunauthor.c dvduncompile.c common.h dvduncompile.h compat.c compat.h
+-dvdunauthor_LDADD = $(XML_LIBS) $(LIBICONV) -ldvdread
++dvdunauthor_LDADD = $(XML2_LIBS) $(LIBICONV) -ldvdread
+ 
+ spumux_SOURCES = subgen.c subgen.h rgb.h \
+     subgen-parse-xml.c readxml.c readxml.h \
+     subgen-encode.c subgen-image.c subglobals.h \
+     conffile.c conffile.h compat.c compat.h common.h \
+     subrender.c subrender.h subreader.c subreader.h subfont.c subfont.h
+-spumux_LDADD = $(XML_LIBS) $(MAGICK_LIBS) $(FREETYPE_LIBS) \
++spumux_LDADD = $(XML2_LIBS) $(MAGICK_LIBS) $(FREETYPE_LIBS) \
+     $(FRIBIDI_LIBS) $(FONTCONFIG_LIBS) $(LIBICONV) -lm
+ 
+ spuunmux_SOURCES = spuunmux.c rgb.h compat.c compat.h common.h conffile.h conffile.c