Note: Since 5.10.1 is not upstream, there might be changes in packages versions, so downloading patches as described below might not work. I’ll try to update this entry to reflect the correct links, but in case of problems just go to http://patch-tracker.debian.org/package/perl, select the current version of Perl 5.10.1 and download mod_paths.diff manually.

After reading encouragingly simple instructions on compiling Perl 5.10.1, I decided to compile Perl — for the first time — on my own.

Everything went fine, but after installation it occurred that the order of directories on @INC is “core, vendor, site”, where the expected — after using Debian’s Perl for years — was “site, vendor, core”. Apparently a bug (for most), with no chance to be corrected due to backward compatibility.

So, I applied a patch from Debian, which corrects the order. Note, that besides correcting the order, the patch adds /etc/perl at the beginning of @INC and /usr/local/lib/site_perl at the end. This is fine with me, but you can remove it from the code if you wish.

mod_paths.diff:

Subject: Tweak @INC so that the ordering is:

    etc (for config files)
    site (5.8.1)
    vendor (all)
    core (5.8.1)
    site (version-indep)
    site (pre-5.8.1)

The rationale being that an admin (via site), or module packager
(vendor) can chose to shadow core modules when there is a newer
version than is included in core.


---
 perl.c |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/perl.c b/perl.c
index 94f2b13..5a6744a 100644
--- a/perl.c
+++ b/perl.c
@@ -4879,9 +4879,14 @@ S_init_perllib(pTHX)
     incpush(APPLLIB_EXP, TRUE, TRUE, TRUE, TRUE);
 #endif

+#ifdef DEBIAN
+    /* for configuration where /usr is mounted ro (CPAN::Config, Net::Config) */
+    incpush("/etc/perl", FALSE, FALSE, FALSE, FALSE);
+#else
 #ifdef ARCHLIB_EXP
     incpush(ARCHLIB_EXP, FALSE, FALSE, TRUE, TRUE);
 #endif
+#endif
 #ifdef MACOS_TRADITIONAL
     {
    Stat_t tmpstatbuf;
@@ -4906,11 +4911,13 @@ S_init_perllib(pTHX)
 #ifndef PRIVLIB_EXP
 #  define PRIVLIB_EXP "/usr/local/lib/perl5:/usr/local/lib/perl"
 #endif
+#ifndef DEBIAN
 #if defined(WIN32)
     incpush(PRIVLIB_EXP, TRUE, FALSE, TRUE, TRUE);
 #else
     incpush(PRIVLIB_EXP, FALSE, FALSE, TRUE, TRUE);
 #endif
+#endif

 #ifdef SITEARCH_EXP
     /* sitearch is always relative to sitelib on Windows for
@@ -4954,6 +4961,61 @@ S_init_perllib(pTHX)
     incpush(PERL_VENDORLIB_STEM, FALSE, TRUE, TRUE, TRUE);
 #endif

+#ifdef DEBIAN
+    incpush(ARCHLIB_EXP, FALSE, FALSE, TRUE, FALSE);
+    incpush(PRIVLIB_EXP, FALSE, FALSE, TRUE, FALSE);
+
+    /* Non-versioned site directory for local modules and for
+       compatability with the previous packages' site dirs */
+    incpush("/usr/local/lib/site_perl", TRUE, FALSE, FALSE, FALSE);
+
+#ifdef PERL_INC_VERSION_LIST
+    {
+   struct stat s;
+
+   /* add small buffer in case old versions are longer than the
+      current version */
+   char sitearch[sizeof(SITEARCH_EXP)+16] = SITEARCH_EXP;
+   char sitelib[sizeof(SITELIB_EXP)+16] = SITELIB_EXP;
+   char const *vers[] = { PERL_INC_VERSION_LIST };
+   char const **p;
+
+   char *arch_vers = strrchr(sitearch, '/');
+   char *lib_vers = strrchr(sitelib, '/');
+
+   if (arch_vers && isdigit(*++arch_vers))
+       *arch_vers = 0;
+   else
+       arch_vers = 0;
+
+   if (lib_vers && isdigit(*++lib_vers))
+       *lib_vers = 0;
+   else
+       lib_vers = 0;
+
+   /* there is some duplication here as incpush does something
+      similar internally, but required as sitearch is not a
+      subdirectory of sitelib */
+   for (p = vers; *p; p++)
+   {
+       if (arch_vers)
+       {
+       strcpy(arch_vers, *p);
+       if (PerlLIO_stat(sitearch, &s) >= 0 && S_ISDIR(s.st_mode))
+           incpush(sitearch, FALSE, FALSE, FALSE, FALSE);
+       }
+
+       if (lib_vers)
+       {
+       strcpy(lib_vers, *p);
+       if (PerlLIO_stat(sitelib, &s) >= 0 && S_ISDIR(s.st_mode))
+           incpush(sitelib, FALSE, FALSE, FALSE, FALSE);
+       }
+   }
+    }
+#endif
+#endif
+
 #ifdef PERL_OTHERLIBDIRS
     incpush(PERL_OTHERLIBDIRS, TRUE, TRUE, TRUE, TRUE);
 #endif
-- 
tg: (daf8b46..) debian/mod_paths (depends on: upstream)

So, my modified compilation instructions with Ubuntu’s “taste” look like:

wget http://www.cpan.org/modules/by-authors/id/D/DA/DAPM/perl-5.10.1.tar.bz2
wget http://patch-tracker.debian.org/patch/series/dl/perl/5.10.1-7/debian/mod_paths.diff
tar xjf perl-5.10.1.tar.bz2
cd perl-5.10.1
patch -b -p1 <../mod_paths.diff
perl Configure -de -Dprefix=${HOME}/local -Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=i486-linux-gnu -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Doptimize=-O2
make
make test
make install

First, I setup SSH tunnel to avoid firewall restrictions:

ssh SERVER -L 3633:localhost:3632

and run a build on the local machine

DISTCC_HOSTS='localhost:3633' CCACHE_PREFIX='distcc' CXX='ccache g++' make -j8

The compilation chain is as follow:

1. ccache is run instead of g++.
2. ccache checks if it has a locally (on the client) cached version of compilation result. If so, the result is returned.
3. If not, distcc is called and performs compilation on the SERVER.
4. Compilation result is stored in ccache’s cache and “returned back”.