{gcc7{,Stdenv},gfortran7}: drop

Release branch from 7½ years ago, no update in 5 years, unsupported
upstream, and unused in tree.

pkgs/development/compilers/gcc/all.nix

@@ -26,7 +26,7 @@ let
         threadsCross = if stdenv.targetPlatform != stdenv.buildPlatform then threadsCross else { };
         isl = if       stdenv.hostPlatform.isDarwin then null
               else if    atLeast "9"   then isl_0_20
-              else    /* atLeast "7" */     isl_0_17;
+              else    /* atLeast "8" */     isl_0_17;
       } // lib.optionalAttrs (!(atLeast "9")) {
         # gcc 10 is too strict to cross compile gcc <= 8
         stdenv = if (stdenv.targetPlatform != stdenv.buildPlatform) && stdenv.cc.isGNU then gcc9Stdenv else stdenv;

pkgs/development/compilers/gcc/default.nix

@@ -68,15 +68,13 @@ let
   atLeast11 = versionAtLeast version "11";
   atLeast10 = versionAtLeast version "10";
   atLeast9  = versionAtLeast version  "9";
-  atLeast8  = versionAtLeast version  "8";
   is14 = majorVersion == "14";
   is13 = majorVersion == "13";
   is12 = majorVersion == "12";
   is11 = majorVersion == "11";
   is10 = majorVersion == "10";
   is9  = majorVersion == "9";
   is8  = majorVersion == "8";
-  is7  = majorVersion == "7";
 
     disableBootstrap = atLeast11 && !stdenv.hostPlatform.isDarwin && (atLeast12 -> !profiledCompiler);
 
@@ -166,7 +164,7 @@ assert stdenv.buildPlatform.isDarwin -> gnused != null;
 
 # The go frontend is written in c++
 assert langGo -> langCC;
-assert (!is7 && !is8) -> (langAda -> gnat-bootstrap != null);
+assert (!is8) -> (langAda -> gnat-bootstrap != null);
 
 # TODO: fixup D bootstapping, probably by using gdc11 (and maybe other changes).
 #   error: GDC is required to build d
@@ -261,9 +259,7 @@ pipe ((callFile ./common/builder.nix {}) ({
 
   configurePlatforms = [ "build" "host" "target" ];
 
-  configureFlags = (callFile ./common/configure-flags.nix { })
-    ++ optional (is7 && targetPlatform.isAarch64) "--enable-fix-cortex-a53-843419"
-    ++ optional (is7 && targetPlatform.isNetBSD) "--disable-libcilkrts";
+  configureFlags = callFile ./common/configure-flags.nix { };
 
   inherit targetConfig;
 
@@ -319,11 +315,7 @@ pipe ((callFile ./common/builder.nix {}) ({
       EXTRA_FLAGS_FOR_TARGET
       EXTRA_LDFLAGS_FOR_TARGET
       ;
-  } // optionalAttrs is7 {
-    NIX_CFLAGS_COMPILE = optionalString (stdenv.cc.isClang && langFortran) "-Wno-unused-command-line-argument"
-      # Downgrade register storage class specifier errors to warnings when building a cross compiler from a clang stdenv.
-      + optionalString (stdenv.cc.isClang && targetPlatform != hostPlatform) " -Wno-register";
-  } // optionalAttrs (!is7 && !atLeast12 && stdenv.cc.isClang && targetPlatform != hostPlatform) {
+  } // optionalAttrs (!atLeast12 && stdenv.cc.isClang && targetPlatform != hostPlatform) {
     NIX_CFLAGS_COMPILE = "-Wno-register";
   });
 
@@ -332,13 +324,12 @@ pipe ((callFile ./common/builder.nix {}) ({
     isGNU = true;
     hardeningUnsupportedFlags =
       optional (
-        (targetPlatform.isAarch64 && !atLeast9) || !atLeast8
+        targetPlatform.isAarch64 && !atLeast9
       ) "stackclashprotection"
       ++ optional (!atLeast11) "zerocallusedregs"
       ++ optionals (!atLeast12) [ "fortify3" "trivialautovarinit" ]
       ++ optional (!(
-        atLeast8
-        && targetPlatform.isLinux
+        targetPlatform.isLinux
         && targetPlatform.isx86_64
         && targetPlatform.libc == "glibc"
       )) "shadowstack"
@@ -371,8 +362,6 @@ pipe ((callFile ./common/builder.nix {}) ({
   preBuild = ''
     makeFlagsArray+=('STRIP=${getBin cctools}/bin/${stdenv.cc.targetPrefix}strip')
   '';
-} // optionalAttrs (!atLeast8) {
-  doCheck = false; # requires a lot of tools, causes a dependency cycle for stdenv
 } // optionalAttrs enableMultilib {
   dontMoveLib64 = true;
 }