Use libpaper 2 instead of non-portable locale call to get default pap…

…er size

libpaper also allows the user to configure the default paper size.

Since libpaper supports sizes unknown to the geometry package, always supply
the dimensions rather than trying to use the name, but print the name in
--help.

This fixes issue #48.

README.md

@@ -93,10 +93,12 @@ For those scripts and for more information on them, please now see
 - A working, up-to-date installation of LaTeX (including at least one of 
   `pdflatex`, `lualatex` or `xelatex`)
 - A working installation of the LaTeX package 
-  [**pdfpages**](http://www.ctan.org/tex-archive/macros/latex/contrib/pdfpages) 
+  [**pdfpages**](https://www.ctan.org/tex-archive/macros/latex/contrib/pdfpages)
   (version 0.4f or later)
   and
-[**geometry**](http://www.ctan.org/tex-archive/macros/latex/contrib/geometry).
+[**geometry**](https://www.ctan.org/tex-archive/macros/latex/contrib/geometry).
+
+With [libpaper](https://github.com/rrthomas/libpaper) version 2 or later installed, `pdfjam` will be able to find your default paper size, which you can configure if desired.
 
 For some years now, **pdfjam** has been included in the _TeX Live_ distribution, 
 which includes all the necessary programs and packages to make `pdfjam` run smoothly.

bin/pdfjam

@@ -212,22 +212,19 @@ suffix='pdfjam'            ##  Default filename suffix to be used when
 ##
 preamble=''                ##  Default LaTeX preamble string.
 ##
-##  Guess default paper size from locale if possible, otherwise A4
-##
-if command -v locale >/dev/null ; then
-    paperheight=$(locale -k LC_PAPER | sed -e '1!d' -e 's/.*=//') ;
-    case $paperheight in
-	297)
-	    paper='a4paper' ;
-	    ;;
-	279)
-	    paper='letterpaper' ;
-	    ;;
-	*)
-	    paper='a4paper' ;
-	    ;;
-    esac
-else paper='a4paper' ;  ## fallback paper size is ISO A4
+##  Get default paper size from libpaper >= 2 if possible, otherwise guess A4
+##
+if command -v paper >/dev/null ; then
+    paperspec=$(paper)
+    paperdimensions=$(echo "$paperspec" | cut -f 2 -d " ")
+    paperunit=$(echo "$paperspec" | cut -f 3 -d " ")
+    if test "$paperunit" = "pt"; then paperunit=bp; fi
+    paperwidth=$(echo "$paperdimensions" | cut -f 1 -d "x")
+    paperheight=$(echo "$paperdimensions" | cut -f 2 -d "x")
+    papersize="papersize={$paperheight$paperunit,$paperwidth$paperunit}"
+    paper='' ## We might not have a LaTeX-compatible name
+else
+    paper='a4paper'  ## fallback paper size is ISO A4
 fi
 ##
 ##  END OF SETTINGS MADE DIRECTLY WITHIN THE SCRIPT