gnu: gcc-4.7: Fix build with gcc-14.

This gets us past the ucontext_t problem, next up:

    In file included from /tmp/guix-build-gcc-fixed-4.7.4.drv-0/build/x86_64-unknown-linux-gnu/libstdc++-v3/include/cstdlib:66:0,
                     from ../../../../gcc-4.7.4/libstdc++-v3/libsupc++/eh_catch.cc:25:
    /gnu/store/d0x6p8327didrav23b1xq9gdawn0b906-gcc-14.2.0/include/c++/stdlib.h:38:12: error: ‘std::abort’ has not been declared

* gnu/packages/patches/gcc-4.7-ucontext-type-confusion.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/gcc.scm (gcc-4.7): Use it.
[arguments]: Use CXX="g++ c++03" in #:configure-flags.

Change-Id: I9c43d5371aa491bb47eaba26f2d21e8500dc1955

gnu/local.mk

@@ -1345,6 +1345,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gcc-cross-environment-variables.patch	\
   %D%/packages/patches/gcc-cross-gxx-include-dir.patch          \
   %D%/packages/patches/gcc-fix-texi2pod.patch			\
+  %D%/packages/patches/gcc-4.7-ucontext-type-confusion.patch	\
   %D%/packages/patches/gcc-4.8-libsanitizer-fix.patch		\
   %D%/packages/patches/gcc-4.9-inline.patch		\
   %D%/packages/patches/gcc-4.9-libsanitizer-fix.patch		\

gnu/packages/gcc.scm

@@ -177,7 +177,8 @@ (define-public gcc-4.7
                   (base32
                    "10k2k71kxgay283ylbbhhs51cl55zn2q38vj5pk4k950qdnirrlj"))
                  (patches (search-patches "gcc-4-compile-with-gcc-5.patch"
-                                          "gcc-fix-texi2pod.patch"))))
+                                          "gcc-fix-texi2pod.patch"
+                                          "gcc-4.7-ucontext-type-confusion.patch"))))
        (build-system gnu-build-system)
 
        ;; Separate out the run-time support libraries because all the
@@ -201,7 +202,8 @@ (define-public gcc-4.7
                                ;; incompatible with some earlier versions.
                                ;; Force an earlier C++ standard while building.
                                (cond
-                                 ((version-prefix? "4.8" version)
+                                ((or (version-prefix? "4.7" version)
+                                     (version-prefix? "4.8" version))
                                   `(cons "CXX=g++ -std=c++03" ,flags))
                                  ((or (version-prefix? "4.9" version)
                                       (version-prefix? "5" version))

gnu/packages/patches/gcc-4.7-ucontext-type-confusion.patch

@@ -0,0 +1,25 @@
+From ef0d1ac2580b43535965eb4b31f077f355660215 Mon Sep 17 00:00:00 2001
+From: Ekaitz Zarraga <ekaitz@elenq.tech>
+Date: Wed, 30 Mar 2022 13:41:15 +0200
+Subject: [PATCH] Fix ucontext_t issue
+
+---
+ libgcc/config/i386/linux-unwind.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/libgcc/config/i386/linux-unwind.h b/libgcc/config/i386/linux-unwind.h
+index cd9a9a1e2b6..62ce4e44d54 100644
+--- a/libgcc/config/i386/linux-unwind.h
++++ b/libgcc/config/i386/linux-unwind.h
+@@ -53,7 +53,7 @@ x86_64_fallback_frame_state (struct _Unwind_Context *context,
+   if (*(unsigned char *)(pc+0) == 0x48
+       && *(unsigned long long *)(pc+1) == RT_SIGRETURN_SYSCALL)
+     {
+-      struct ucontext *uc_ = context->cfa;
++      struct ucontext_t *uc_ = context->cfa;
+       /* The void * cast is necessary to avoid an aliasing warning.
+          The aliasing warning is correct, but should not be a problem
+          because it does not alias anything.  */
+-- 
+2.46.0
+