Replace literal "." by currentdir

This is going to be useful as it splits the cases where "." means
'current dir' from other use cases. Use where "." is used in e.g. path
splitting are retained: they are in a way distinct to the current dir
concept.

There are a few places that the split between 'current dir' and 'main
dir' is not clear, as well as those that need further attention to have
a fully-working docfiledir and to introduce sourcefildir. Those may need
further work/discussion.

l3build.lua

@@ -61,12 +61,13 @@ end
 
 -- Directory structure for the build system
 -- Use Unix-style path separators
-maindir = maindir or "."
+currentdir = "."
+maindir    = maindir or currentdir
 
 -- Substructure for file locations
-docfiledir  = docfiledir  or maindir
+docfiledir  = docfiledir  or currentdir
 supportdir  = supportdir  or maindir .. "/support"
-testfiledir = testfiledir or maindir .. "/testfiles"
+testfiledir = testfiledir or currentdir .. "/testfiles"
 testsuppdir = testsuppdir or testfiledir .. "/support"
 
 -- Structure within a development area
@@ -838,7 +839,7 @@ function checkinit()
   for _,i in ipairs(filelist(localdir)) do
     cp(i, localdir, testdir)
   end
-  bundleunpack({".", testfiledir})
+  bundleunpack({currentdir, testfiledir})
   for _,i in ipairs(installfiles) do
     cp(i, unpackdir, testdir)
   end
@@ -871,7 +872,7 @@ function copyctan()
       }
     ) do
     for _,j in ipairs(i) do
-      cp(j, ".", ctandir .. "/" .. ctanpkg)
+      cp(j, currentdir, ctandir .. "/" .. ctanpkg)
     end
   end
 end
@@ -918,7 +919,7 @@ function copytds()
   )
   install(unpackdir, "makeindex", {makeindexfiles}, true)
   install(unpackdir, "bibtex/bst", {bstfiles}, true)
-  install(".", "source", {sourcelist})
+  install(currentdir, "source", {sourcelist})
   install(unpackdir, "tex", {installfiles})
 end
 
@@ -1921,15 +1922,15 @@ function clean()
     cleandir(typesetdir) +
     cleandir(unpackdir)
   for _,i in ipairs(cleanfiles) do
-    errorlevel = rm(".", i) + errorlevel
+    errorlevel = rm(currentdir, i) + errorlevel
   end
   return errorlevel
 end
 
 function bundleclean()
   local errorlevel = call(modules, "clean")
   for _,i in ipairs(cleanfiles) do
-    errorlevel = rm(".", i) + errorlevel
+    errorlevel = rm(maindir, i) + errorlevel
   end
   return (
     errorlevel     +
@@ -1945,7 +1946,7 @@ function cmdcheck()
   depinstall(checkdeps)
   for _,i in ipairs({bibfiles, docfiles, sourcefiles, typesetfiles}) do
     for _,j in ipairs(i) do
-      cp(j, ".", testdir)
+      cp(j, currentdir, testdir)
     end
   end
   for _,i in ipairs(typesetsuppfiles) do
@@ -1955,7 +1956,7 @@ function cmdcheck()
   local localdir = abspath(localdir)
   print("Checking source files")
   for _,i in ipairs(cmdchkfiles) do
-    for _,j in ipairs(filelist(".", i)) do
+    for _,j in ipairs(filelist(currentdir, i)) do
       print("  " .. jobname(j))
       run(
         testdir,
@@ -2031,7 +2032,7 @@ function ctan(standalone)
   end
   if errorlevel == 0 then
     for _,i in ipairs(textfiles) do
-      for _,j in pairs({unpackdir, "."}) do
+      for _,j in pairs({unpackdir, currentdir}) do
         cp(i, j, ctandir .. "/" .. ctanpkg)
         cp(i, j, tdsdir .. "/doc/" .. tdsroot .. "/" .. bundle)
       end
@@ -2041,7 +2042,7 @@ function ctan(standalone)
       cp(ctanpkg .. ".tds.zip", tdsdir, ctandir)
     end
     dirzip(ctandir, ctanpkg)
-    cp(ctanpkg .. ".zip", ctandir, ".")
+    cp(ctanpkg .. ".zip", ctandir, currentdir)
   else
     print("\n====================")
     print("Typesetting failed, zip stage skipped!")
@@ -2060,13 +2061,13 @@ function bundlectan()
     local excludelist = { }
     for _,i in ipairs(exclude) do
       for _,j in ipairs(i) do
-        for _,k in ipairs(filelist(".", j)) do
+        for _,k in ipairs(filelist(currentdir, j)) do
           excludelist[k] = true
         end
       end
     end
     for _,i in ipairs(include) do
-      for _,j in ipairs(filelist(".", i)) do
+      for _,j in ipairs(filelist(currentdir, i)) do
         if not excludelist[j] then
           insert(includelist, j)
         end
@@ -2114,7 +2115,7 @@ function doc(files)
     cp(i, supportdir, typesetdir)
   end
   depinstall(typesetdeps)
-  unpack({sourcefiles, typesetsourcefiles}, {".", docfiledir})
+  unpack({sourcefiles, typesetsourcefiles}, {currentdir, docfiledir})
   -- Main loop for doc creation
   local done = {}
   for _, typesetfiles in ipairs({typesetdemofiles, typesetfiles}) do
@@ -2312,7 +2313,7 @@ function setversion(dir)
   end
   local date = options["date"] or os_date("%Y-%m-%d")
   local version = options["version"] or -1
-  local dir = dir or "."
+  local dir = dir or currentdir
   for _,i in pairs(versionfiles) do
     for _,j in pairs(filelist(dir, i)) do
       rewrite(dir, j, date, version)
@@ -2352,7 +2353,7 @@ bundleunpack = bundleunpack or function(sourcedirs, sources)
   if errorlevel ~=0 then
     return errorlevel
   end
-  for _,i in ipairs(sourcedirs or {"."}) do
+  for _,i in ipairs(sourcedirs or {currentdir}) do
     for _,j in ipairs(sources or {sourcefiles}) do
       for _,k in ipairs(j) do
         errorlevel = cp(k, i, unpackdir)