Use pkg-config for libFLAC

Don't use FLAC_CFLAGS because it contains -I/usr/lib/FLAC which breaks
anything using assert(), due to FLAC's own assert.h.

configure.in

@@ -103,6 +103,10 @@ if test x$use_oggvorbis = xtrue; then
 	PKG_CHECK_MODULES(OGGVORBIS, [ ogg vorbis vorbisfile ])
 fi
 
+if test x$use_flac = xtrue; then
+	PKG_CHECK_MODULES(FLAC, [ flac ])
+fi
+
 if test x$use_ffmpeg = xtrue; then
 	PKG_CHECK_MODULES(FFMPEG, [ libavcodec libavformat ])
 fi
@@ -118,18 +122,6 @@ AC_ARG_WITH(static-libs,
 AC_CHECK_HEADERS(getopt.h,,)
 AC_CHECK_HEADERS(stdint.h,,)
 
-if test x$use_flac = xtrue; then
-  AC_CHECK_HEADERS(FLAC/metadata.h,, [
-   AC_MSG_ERROR([FLAC/metadata.h not found... Must have libFLAC installed for FLAC support])])
-  AC_CHECK_LIB(FLAC,FLAC__metadata_chain_read,,echo "Must have libFLAC for FLAC support";exit)
-
-  if test x"$STATIC_LIBS" != x"no"; then
-    LIBS="${LIBS} ${STATIC_LIBS}/libFLAC.a"
-  else
-    LIBS="${LIBS} -lFLAC"
-  fi
-fi
-
 if test x$use_musepack = xtrue; then
   AC_PATH_PROG(TAGLIB_CONFIG, taglib-config, no)
   AC_CHECK_HEADERS(taglib/tag_c.h,, [

src/Makefile.am

@@ -25,7 +25,7 @@ endif
 wavstreamer_SOURCES = wavstreamer.c
 
 mt_daapd_CPPFLAGS = @AVAHI_CFLAGS@ @SQLITE3_CFLAGS@ @ID3TAG_CFLAGS@ @OGGVORBIS_CFLAGS@
-mt_daapd_LDADD = @AVAHI_LIBS@ @SQLITE3_LIBS@ @ID3TAG_LIBS@ @OGGVORBIS_LIBS@
+mt_daapd_LDADD = @AVAHI_LIBS@ @SQLITE3_LIBS@ @ID3TAG_LIBS@ @OGGVORBIS_LIBS@ @FLAC_LIBS@
 mt_daapd_SOURCES = main.c daapd.h rend.h webserver.c \
 	webserver.h configfile.c configfile.h err.c err.h restart.c restart.h \
 	mp3-scanner.h mp3-scanner.c \

src/scan-flac.c

@@ -23,7 +23,6 @@
 #  include "config.h"
 #endif
 
-#define _POSIX_PTHREAD_SEMANTICS
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>