Set correct value for includedir in pkg-config files.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@12865 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -2101,7 +2101,6 @@ fi
 
 
 # build pkg-config files
-# FIXME: includedir is hardcoded and may differ from the real path.
 
 pkgconfig_generate(){
 name=$1
@@ -2113,7 +2112,7 @@ cat <<EOF >$name.pc
 prefix=$prefix
 exec_prefix=\${prefix}
 libdir=$libdir
-includedir=\${prefix}/include
+includedir=$incdir
 
 Name: $name
 Description: $comment