From 7fdd21054366fde6eb8f0bf0a2fe540fd38140d4 Mon Sep 17 00:00:00 2001
From: Joseph Heenan <joseph@heenan.me.uk>
Date: Sun, 29 May 2016 11:08:36 +0100
Subject: [PATCH 1/2] Produce more helpful error if pkg-config not installed

Currently if users run autoreconf then configure without having
pkg-config installed, they see:

./configure: line 5283: syntax error near unexpected token FFMPEG,'
./configure: line 5283:    PKG_CHECK_MODULES(FFMPEG, libavutil
libavformat libavcodec libswscale, HAVE_FFMPEG=yes)'

This is not hugely helpful and causes support queries and confusion.
It is because the pkg.m4 file that defines PKG_CHECK_MODULES is not
available of pkg-config is not installed.

To work around this, remove PKG_CHECK_MODULES and do roughly the
equivalent calling pkg-config directly. To mirror the current
behaviour, we also add a test for pkg-config being present and abort
if it is not. (I am not 100% sure this is the desired behaviour, but
regardless this commit is still an improvement on what we currently
have.)
---
 configure.ac | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 155c12cc..900051ef 100644
--- a/configure.ac
+++ b/configure.ac
@@ -383,7 +383,19 @@ AS_IF([test "x$with_ffmpeg" != "xno"], [
 	      PKG_CONFIG_PATH=${with_ffmpeg}/lib/pkgconfig:$PKG_CONFIG_PATH
 	      export PKG_CONFIG_PATH
 	])
-	PKG_CHECK_MODULES([FFMPEG], libavutil libavformat libavcodec libswscale, HAVE_FFMPEG=yes)
+
+       AC_CHECK_PROG([PKGCONFIG],[pkg-config],[yes],[no])
+       AM_CONDITIONAL([FOUND_PKGCONFIG], [test "x$PKGCONFIG" = xyes])
+       AM_COND_IF([FOUND_PKGCONFIG],,[AC_MSG_ERROR([required package 'pkg-config' not found, please check motion_guide.html and install necessary dependencies.])])
+
+       AC_SUBST(FFMPEG_LIBS)
+       AC_SUBST(FFMPEG_CFLAGS)
+       FFMPEG_DEPS="libavutil libavformat libavcodec libswscale"
+       if pkg-config $FFMPEG_DEPS; then
+               FFMPEG_CFLAGS=`pkg-config --cflags $FFMPEG_DEPS`
+               FFMPEG_LIBS=`pkg-config --libs $FFMPEG_DEPS`
+               HAVE_FFMPEG="yes"
+       fi
 ])
 
 AS_IF([test "${HAVE_FFMPEG}" = "yes" ], [

From 55945b6d7d8f91258f1467198a437ec394be1000 Mon Sep 17 00:00:00 2001
From: Mr-DaveDev <MotionMrDaveDev@gmail.com>
Date: Thu, 18 Aug 2016 21:23:58 -0600
Subject: [PATCH 2/2] Updated configure.ac for pkg-config

---
 CHANGELOG    |  1 +
 configure.ac | 14 ++++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 40219cc8..09a9b046 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,5 @@
 Summary of Changes
+   * Better messages for pkg-config
    * Fix timelapse crash when selecting mpeg4
 Version 3.4.1 Changes Below
    * Added suggestion for including pkgconf as part of build requirements
diff --git a/configure.ac b/configure.ac
index 900051ef..a256f3d4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -368,6 +368,14 @@ if test x$JPEG_SUPPORT != xyes ; then
   )
 fi
 
+#
+# Check for the pkg-config.  
+#
+
+AC_CHECK_PROG([PKGCONFIG],[pkg-config],[yes],[no])
+AM_CONDITIONAL([FOUND_PKGCONFIG], [test "x$PKGCONFIG" = xyes])
+AM_COND_IF([FOUND_PKGCONFIG],,[AC_MSG_ERROR([Required package 'pkg-config' not found, please check motion_guide.html and install necessary dependencies.])])
+
 
 #
 # Check for libavcodec and libavformat from ffmpeg
@@ -384,10 +392,6 @@ AS_IF([test "x$with_ffmpeg" != "xno"], [
 	      export PKG_CONFIG_PATH
 	])
 
-       AC_CHECK_PROG([PKGCONFIG],[pkg-config],[yes],[no])
-       AM_CONDITIONAL([FOUND_PKGCONFIG], [test "x$PKGCONFIG" = xyes])
-       AM_COND_IF([FOUND_PKGCONFIG],,[AC_MSG_ERROR([required package 'pkg-config' not found, please check motion_guide.html and install necessary dependencies.])])
-
        AC_SUBST(FFMPEG_LIBS)
        AC_SUBST(FFMPEG_CFLAGS)
        FFMPEG_DEPS="libavutil libavformat libavcodec libswscale"
@@ -395,6 +399,8 @@ AS_IF([test "x$with_ffmpeg" != "xno"], [
                FFMPEG_CFLAGS=`pkg-config --cflags $FFMPEG_DEPS`
                FFMPEG_LIBS=`pkg-config --libs $FFMPEG_DEPS`
                HAVE_FFMPEG="yes"
+       else
+              AC_MSG_ERROR([Required ffmpeg packages 'libavutil-dev libavformat-dev libavcodec-dev libswscale-dev' were not found.  Please check motion_guide.html and install necessary dependencies or use the '--without-ffmpeg' configuration option.])
        fi
 ])