bootstrap: Reduced Binary Seed bootstrap for x86_64 too.

* gnu/packages/bootstrap.scm (%bootstrap-inputs): Replace %bootstrap-libc,
%bootstrap-gcc, and %bootstrap-binutils with Mes seeds for x86_64 too.
* gnu/packages/commencement.scm (tcc-boot0, tcc-boot, gcc-mesboot1,
gcc-mesboot1-wrapper, m4-mesboot, %bootstrap-inputs+toolchain,
libstdc++-boot0, gcc-boot0, bison-boot0): For x86_64-linux, use i686-linux
glibc-dynamic-linker and Mes bootstrap settings.
(gcc-boot0-intermediate-wrapped): New variable, extract from
static-bash-for-glibc.
(static-bash-for-glibc): Use it.
(gcc-final): Copy gmp&co phase from gcc-boot0, inherit other arguments
from gcc; avoid i686-linux impersonation from gcc-boot0.
* doc/guix.texi (Bootstrapping, Reduced Binary Seed Bootstrap): Note
x86_64-linux also as Reduced Binary Seed bootstrap.

doc/guix.texi

@@ -23554,8 +23554,8 @@ Binutils, libc, and the other packages mentioned above---the
 These bootstrap binaries are ``taken for granted'', though we can also
 re-create them if needed (more on that later).
 
-For @code{i686-linux} the Guix bootstrap process is more elaborate,
+For @code{i686-linux} and @code{x86_64-linux} the Guix bootstrap process is
-@pxref{Reduced Binary Seed Bootstrap}.
+more elaborate, @pxref{Reduced Binary Seed Bootstrap}.
 
 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
 
@@ -23725,10 +23725,10 @@ problem: the current combined size of these bootstrap binaries is about 250MB
 (@pxref{Bootstrappable Builds,,, mes, Mes Reference Manual}).  Auditing or
 even inspecting these is next to impossible.
 
-For @code{i686-linux}, Guix now features a ``Reduced Binary Seed'' bootstrap
+For @code{i686-linux} and @code{x86_64-linux}, Guix now features a ``Reduced
-@footnote{We would like to say: ``Full Source Bootstrap'' and while we are
+Binary Seed'' bootstrap @footnote{We would like to say: ``Full Source
-working towards that goal it would be hyperbole to use that term for what we
+Bootstrap'' and while we are working towards that goal it would be hyperbole
-do now.}.
+to use that term for what we do now.}.
 
 The Reduced Binary Seed bootstrap removes the most critical tools---from a
 trust perspective---from the bootstrap binaries: GCC, Binutils and the GNU C

gnu/packages/bootstrap.scm

@@ -656,13 +656,14 @@ (define (%bootstrap-inputs)
   ;; The initial, pre-built inputs.  From now on, we can start building our
   ;; own packages.
   `(,@(match (%current-system)
-        ("i686-linux" `(("linux-libre-headers" ,%bootstrap-linux-libre-headers)
+        ((or "i686-linux" "x86_64-linux")
+         `(("linux-libre-headers" ,%bootstrap-linux-libre-headers)
            ("mescc-tools-seed" ,%mescc-tools-seed)
            ("mes-seed" ,%mes-seed)
            ("srfi-43" ,%srfi-43 )
            ("tinycc-seed" ,%tinycc-seed)))
-
+        (_
-        (_  `(("libc" ,%bootstrap-glibc)
+         `(("libc" ,%bootstrap-glibc)
            ("gcc" ,%bootstrap-gcc)
            ("binutils" ,%bootstrap-binutils))))
     ("coreutils&co" ,%bootstrap-coreutils&co)

gnu/packages/commencement.scm

@@ -383,7 +383,8 @@ (define tcc-boot0
                        (mescc-tools (assoc-ref %build-inputs "mescc-tools"))
                        (libc (assoc-ref %build-inputs "libc"))
                        (interpreter (if libc
-                                        (string-append libc ,(glibc-dynamic-linker))
+                                        ;; also for x86_64-linux, we are still on i686-linux
+                                        (string-append libc ,(glibc-dynamic-linker "i686-linux"))
                                         (string-append mes "/lib/mes-loader"))))
                   (setenv "PATH" (string-append
                                   coreutils "/bin"
@@ -488,7 +489,8 @@ (define tcc-boot
                      (tcc (assoc-ref %build-inputs "tcc"))
                      (libc (assoc-ref %build-inputs "libc"))
                      (interpreter (if libc
-                                      (string-append libc ,(glibc-dynamic-linker))
+                                      ;; also for x86_64-linux, we are still on i686-linux
+                                      (string-append libc ,(glibc-dynamic-linker "i686-linux"))
                                       (string-append mes "/lib/mes-loader"))))
                 ;; unpack
                 (setenv "PATH" (string-append
@@ -510,7 +512,8 @@ (define tcc-boot
                      (tcc (assoc-ref %build-inputs "tcc"))
                      (libc (assoc-ref %build-inputs "libc"))
                      (interpreter (if libc
-                                      (string-append libc ,(glibc-dynamic-linker))
+                                      ;; also for x86_64-linux, we are still on i686-linux
+                                      (string-append libc ,(glibc-dynamic-linker "i686-linux"))
                                       (string-append mes "/lib/mes-loader"))))
                 (invoke "tcc"
                         "-vvv"
@@ -1140,7 +1143,7 @@ (define gcc-mesboot1
                            "-B" libc "/lib "
                            "-Wl,-dynamic-linker "
                            "-Wl," libc
-                           ,(glibc-dynamic-linker))))
+                           ,(glibc-dynamic-linker "i686-linux"))))
             (list (string-append "LDFLAGS=" ldflags)
                   (string-append "LDFLAGS_FOR_TARGET=" ldflags))))
         ((#:phases phases)
@@ -1267,7 +1270,8 @@ (define gcc-mesboot1-wrapper
                          (display (string-append "#! " bash "/bin/bash
 exec " gcc "/bin/" program
 " -Wl,--dynamic-linker"
-" -Wl," libc ,(glibc-dynamic-linker)
+;; also for x86_64-linux, we are still on i686-linux
+" -Wl," libc ,(glibc-dynamic-linker "i686-linux")
 " -Wl,--rpath"
 " -Wl," libc "/lib"
 " \"$@\"
@@ -1552,7 +1556,7 @@ (define m4-mesboot
                (sha256
                 (base32
                  "1f9bxj176kf3pvs350w2dfs8jgwhminywri5pyn01b11yc4yhsjw"))))
-     (supported-systems '("i686-linux"))
+     (supported-systems '("i686-linux" "x86_64-linux"))
      (native-inputs `(("mes" ,mes-boot)
                       ("tcc" ,tcc-boot)))
      (arguments
@@ -1572,11 +1576,13 @@ (define (%bootstrap-inputs+toolchain)
   ;; The traditional bootstrap-inputs.  For the i686-linux Reduced Binary Seed
   ;; the actual reduced set with bootstrapped toolchain.
   (append (match (%current-system)
-            ("i686-linux" `(("libc" ,glibc-mesboot)
+            ((or "i686-linux" "x86_64-linux")
+             `(("libc" ,glibc-mesboot)
                ("binutils" ,binutils-mesboot)
                ("gcc-wrapper" ,gcc-mesboot-wrapper)
                ("gcc" ,gcc-mesboot)))
-            (_ '()))
+            (_
+             '()))
           (%bootstrap-inputs)))
 
 (define gnu-make-boot0
@@ -1723,7 +1729,7 @@ (define libstdc++-boot0
          #:validate-runpath? #f
 
          ,@(match (%current-system)
-             ("i686-linux"
+             ((or "i686-linux" "x86_64-linux")
               (substitute-keyword-arguments (package-arguments lib)
                 ((#:phases phases)
                  `(modify-phases ,phases
@@ -1784,6 +1790,17 @@ (define gcc-boot0
                       (remove (cut string-match
                                 "--(with-system-zlib|enable-languages.*)" <>)
                               ,flags)))
+            ((#:make-flags flags)
+             `(let* ((libc        (assoc-ref %build-inputs "libc"))
+                     (libc-native (or (assoc-ref %build-inputs "libc-native")
+                                      libc)))
+                `(,(string-append "LDFLAGS="
+                                  "-Wl,-rpath=" libc-native "/lib "
+                                  "-Wl,-dynamic-linker "
+                                  "-Wl," libc-native ,(glibc-dynamic-linker
+                                                       (match (%current-system)
+                                                         ("x86_64-linux" "i686-linux")
+                                                         (_ (%current-system))))))))
             ((#:phases phases)
              `(modify-phases ,phases
                 (add-after 'unpack 'unpack-gmp&co
@@ -1809,7 +1826,7 @@ (define gcc-boot0
                              (list gmp-6.0 mpfr mpc))
                       #t)))
                 ,(match (%current-system)
-                   ("i686-linux"
+                   ((or "i686-linux" "x86_64-linux")
                     '(add-after 'build 'libtool-workaround
                       (lambda _
                         ;; libtool: install: /gnu/store/7swwdnq02lqk4xkd8740fxdj1h4va38l-bootstrap-binaries-0/bin/install -c .libs/libcc1.so.0.0.0 /gnu/store/8qf47i99nxz9jvrmq5va0g3q1yvs3x74-gcc-cross-boot0-5.5.0-lib/lib/./libcc1.so.0.0.0
@@ -1817,7 +1834,7 @@ (define gcc-boot0
                         (system* "touch"
                                  "libcc1/.libs/libcc1.so.0.0.0"
                                  "libcc1/.libs/libcc1plugin.so.0.0.0"))))
-                   (_ 'identity))
+                   (_ identity))
                 (add-after 'install 'symlink-libgcc_eh
                   (lambda* (#:key outputs #:allow-other-keys)
                     (let ((out (assoc-ref outputs "lib")))
@@ -1904,8 +1921,10 @@ (define bison-boot0
                      #:make-flags `("ARFLAGS=crD"
                                     ,,(match (%current-system)
                                         ;; ranlib: '-D': No such file
-                                      ("i686-linux" "RANLIB=ranlib")
+                                        ((or "i686-linux" "x86_64-linux")
-                                      (_ "RANLIB=ranlib -D"))
+                                         "RANLIB=ranlib")
+                                        (_
+                                         "RANLIB=ranlib -D"))
                                     "V=1"))))))
     (package
       (inherit (package-with-bootstrap-guile
@@ -2156,6 +2175,13 @@ (define (wrap-program program)
        ("bash" ,bash)))
     (inputs '())))
 
+(define (gcc-boot0-intermediate-wrapped)
+  ;; Make the cross-tools GCC-BOOT0 and BINUTILS-BOOT0 available under the
+  ;; non-cross names.
+  (cross-gcc-wrapper gcc-boot0 binutils-boot0
+                     glibc-final-with-bootstrap-bash
+                     (car (assoc-ref (%boot1-inputs) "bash"))))
+
 (define static-bash-for-glibc
   ;; A statically-linked Bash to be used by GLIBC-FINAL in system(3) & co.
   (let ((bash (package
@@ -2177,14 +2203,11 @@ (define static-bash-for-glibc
      (package-with-explicit-inputs
       bash
       (lambda _
-        (let ((gcc  (cross-gcc-wrapper gcc-boot0 binutils-boot0
+        `(("gcc" ,(gcc-boot0-intermediate-wrapped))
-                                       glibc-final-with-bootstrap-bash
-                                       (car (assoc-ref (%boot1-inputs) "bash")))))
-          `(("gcc" ,gcc)
           ("libc" ,glibc-final-with-bootstrap-bash)
           ("libc:static" ,glibc-final-with-bootstrap-bash "static")
           ,@(fold alist-delete (%boot1-inputs)
-                    '("gcc" "libc")))))
+                  '("gcc" "libc"))))
       (current-source-location)
       #:guile %bootstrap-guile))))
 
@@ -2344,17 +2367,7 @@ (define gcc-final
        ;; positive, so turn it off.
        #:validate-runpath? #f
 
-       ;; Build again GMP & co. within GCC's build process, because it's hard
+       ,@(substitute-keyword-arguments (package-arguments gcc)
-       ;; to do outside (because GCC-BOOT0 is a cross-compiler, and thus
-       ;; doesn't honor $LIBRARY_PATH, which breaks `gnu-build-system'.)
-       ,@(substitute-keyword-arguments (package-arguments gcc-boot0)
-           ((#:configure-flags boot-flags)
-            (let loop ((args (package-arguments gcc)))
-              (match args
-                ((#:configure-flags normal-flags _ ...)
-                 normal-flags)
-                ((_ rest ...)
-                 (loop rest)))))
            ((#:make-flags flags)
             ;; Since $LIBRARY_PATH is not honored, add the relevant flags.
             `(let ((zlib (assoc-ref %build-inputs "zlib")))
@@ -2366,8 +2379,33 @@ (define gcc-final
                                          zlib "/lib")
                           flag))
                     ,flags)))
+           ;; Build again GMP & co. within GCC's build process, because it's hard
+           ;; to do outside (because GCC-BOOT0 is a cross-compiler, and thus
+           ;; doesn't honor $LIBRARY_PATH, which breaks `gnu-build-system'.)
            ((#:phases phases)
-            `(alist-delete 'symlink-libgcc_eh ,phases)))))
+            `(modify-phases ,phases
+                (add-after 'unpack 'unpack-gmp&co
+                  (lambda* (#:key inputs #:allow-other-keys)
+                    (let ((gmp  (assoc-ref %build-inputs "gmp-source"))
+                          (mpfr (assoc-ref %build-inputs "mpfr-source"))
+                          (mpc  (assoc-ref %build-inputs "mpc-source")))
+
+                      ;; To reduce the set of pre-built bootstrap inputs, build
+                      ;; GMP & co. from GCC.
+                      (for-each (lambda (source)
+                                  (invoke "tar" "xvf" source))
+                                (list gmp mpfr mpc))
+
+                      ;; Create symlinks like `gmp' -> `gmp-x.y.z'.
+                      ,@(map (lambda (lib)
+                               ;; Drop trailing letters, as gmp-6.0.0a unpacks
+                               ;; into gmp-6.0.0.
+                               `(symlink ,(string-trim-right
+                                           (package-full-name lib "-")
+                                           char-set:letter)
+                                         ,(package-name lib)))
+                             (list gmp-6.0 mpfr mpc))
+                      #t))))))))
 
     ;; This time we want Texinfo, so we get the manual.  Add
     ;; STATIC-BASH-FOR-GLIBC so that it's used in the final shebangs of