bug#25799: [PATCH] gnu: add basic support for "alpha-linux" system

[Sergei Trofimovich]

This change allows cross-building packages
by just using --target=alpha-unknown-linux-gnu re2c:

$ ./pre-inst-env guix build --target=alpha-unknown-linux-gnu re2c
$ file /gnu/store/p1z9iszzb4ng0vzc535sc2ha33ax24l6-re2c-0.16/bin/re2c
/gnu/store/p1z9iszzb4ng0vzc535sc2ha33ax24l6-re2c-0.16/bin/re2c: ELF 64-bit LSB 
executable, Alpha (unofficial), version 1 (SYSV), dynamically linked, 
interpreter 
/gnu/store/0z5d6z3hh41w7z5g2g82zlnwgpbj0i1a-glibc-cross-alpha-unknown-linux-gnu-2.24/lib/ld-linux.so.2,
 for GNU/Linux 3.2.0, not stripped

The only slighty nontrivial change is GLIBC_DYNAMIC_LINKER change:
glibc for alpha uses 'GLIBC_DYNAMIC_LINKER<TAB>"/lib/ld-linux.so.2"'

* gnu/packages/bootstrap.scm (glibc-dynamic-linker): add "/lib/ld-linux.so.2" 
as "alpha-linux" ld.so
* gnu/packages/gcc.scm (gcc-4.7): fix GLIBC_DYNAMIC_LINKER substitution when 
delimiter is a tab
* gnu/packages/linux.scm (system->linux-architecture): add "alpha" arch

Signed-off-by: Sergei Trofimovich <address@hidden>
---
 gnu/packages/bootstrap.scm | 1 +
 gnu/packages/gcc.scm       | 2 +-
 gnu/packages/linux.scm     | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/bootstrap.scm b/gnu/packages/bootstrap.scm
index c8d94c830..b4847094b 100644
--- a/gnu/packages/bootstrap.scm
+++ b/gnu/packages/bootstrap.scm
@@ -167,6 +167,7 @@ successful, or false to signal an error."
         ((string=? system "i586-gnu") "/lib/ld.so.1")
         ((string=? system "i686-gnu") "/lib/ld.so.1")
         ((string=? system "aarch64-linux") "/lib/ld-linux-aarch64.so.1")
+        ((string=? system "alpha-linux") "/lib/ld-linux.so.2")
 
         ;; XXX: This one is used bare-bones, without a libc, so add a case
         ;; here just so we can keep going.
diff --git a/gnu/packages/gcc.scm b/gnu/packages/gcc.scm
index cfd33f85a..7522f1c7f 100644
--- a/gnu/packages/gcc.scm
+++ b/gnu/packages/gcc.scm
@@ -212,7 +212,7 @@ where the OS part is overloaded to denote a specific 
ABI---into GCC
                 ;; Fix the dynamic linker's file name.
                 (substitute* (find-files "gcc/config"
                                          "^(linux|gnu)(64|-elf|-eabi)?\\.h$")
-                  (("#define GLIBC_DYNAMIC_LINKER([^ ]*).*$" _ suffix)
+                  (("#define GLIBC_DYNAMIC_LINKER([^ \t]*).*$" _ suffix)
                    (format #f "#define GLIBC_DYNAMIC_LINKER~a \"~a\"~%"
                            suffix
                            (string-append libc ,(glibc-dynamic-linker)))))
diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index 9212b40a1..7d59faf4a 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -106,6 +106,7 @@
           ((string-prefix? "mips" arch) "mips")
           ((string-prefix? "arm" arch) "arm")
           ((string-prefix? "aarch64" arch) "arm64")
+          ((string-prefix? "alpha" arch) "alpha")
           (else arch))))
 
 (define (linux-libre-urls version)
-- 
2.11.1