configure: simplify get_version()

All libs have version headers now, which allows hardcoding the path.

configure

@@ -3368,22 +3368,22 @@ SAMPLES:=${samples:-\$(LIBAV_SAMPLES)}
 EOF
 
 get_version(){
-    name=$1
-    file=$source_path/$2
+    lcname=$1
+    name=$(toupper $lcname)
+    file=$source_path/$lcname/version.h
     eval $(grep "#define ${name}_VERSION_M" "$file" | awk '{ print $2"="$3 }')
     eval ${name}_VERSION=\$${name}_VERSION_MAJOR.\$${name}_VERSION_MINOR.\$${name}_VERSION_MICRO
-    lcname=$(tolower $name)
     eval echo "${lcname}_VERSION=\$${name}_VERSION" >> config.mak
     eval echo "${lcname}_VERSION_MAJOR=\$${name}_VERSION_MAJOR" >> config.mak
 }
 
-get_version LIBAVCODEC  libavcodec/version.h
-get_version LIBAVDEVICE libavdevice/version.h
-get_version LIBAVFILTER libavfilter/version.h
-get_version LIBAVFORMAT libavformat/version.h
-get_version LIBAVRESAMPLE libavresample/version.h
-get_version LIBAVUTIL   libavutil/version.h
-get_version LIBSWSCALE  libswscale/version.h
+get_version libavcodec
+get_version libavdevice
+get_version libavfilter
+get_version libavformat
+get_version libavresample
+get_version libavutil
+get_version libswscale
 
 cat > $TMPH <<EOF
 /* Automatically generated by configure - do not modify! */