Support wrapping bootstrap CC for autotools

During the initial bootstrap phase, an old autotools project (gcc
4.7.4) is built and this potentially with a new compiler. For some
of the tests carried out by the autotools, the compiler is used
without the CFLAGS provided. Therefore, offer to wrap the compiler
with the given flags to avoid that the autotools draw incorrect
conclusions if the compile attempt fails for a different reason,
e.g., because implicit declarations are now considered errors by
default by modern C compilers.

2 files changed, 163 insertions, 98 deletions

diff --git a/README.md b/README.md
index 781a8d2..6046604 100644
--- a/README.md
+++ b/README.md
@@ -171,6 +171,11 @@ Fields for building the toolchains:
   Library directory of the C library on the build host (default: not set)
 - `HOST_DYNAMIC_LINKER`:
   Absolute path to the dynamic linker on the build host (default: not set)
+- `BOOTSTRAP_WRAP_CC`:
+  If true, when using the bootstrap C compiler with autotools, use a wrapper
+  script calling the compiler with the `BOOTSTRAP_CFLAGS` instead. In this way,
+  it can be avoided that the autotools draw wrong conclusions from calling the
+  compiler without the specified flags (as some tests do).
 - `INCLUDE_LINTER`:
   Add linter to toolchain if supported, e.g., `clang-tidy` (default: `false`)
 
diff --git a/src/bootstrap/stage-0-gcc.TARGETS b/src/bootstrap/stage-0-gcc.TARGETS
index 26fbfa3..ffebd86 100644
--- a/src/bootstrap/stage-0-gcc.TARGETS
+++ b/src/bootstrap/stage-0-gcc.TARGETS
@@ -53,114 +53,174 @@
   , "localbase":
     [["@", "busybox", "", "bootstrap"], ["@", "make", "", "bootstrap"]]
   , "cmds":
-    [ { "type": "join"
-      , "$1":
-        [ "HOST_SYSTEM_HDR_DIR='"
-        , { "type": "lookup"
-          , "key": "HOST_SYSTEM_HDR_DIR"
-          , "map":
-            { "type": "var"
-            , "name": "TOOLCHAIN_CONFIG"
-            , "default": {"type": "empty_map"}
-            }
-          , "default": ""
+    { "type": "++"
+    , "$1":
+      [ [ { "type": "join"
+          , "$1":
+            [ "HOST_SYSTEM_HDR_DIR='"
+            , { "type": "lookup"
+              , "key": "HOST_SYSTEM_HDR_DIR"
+              , "map":
+                { "type": "var"
+                , "name": "TOOLCHAIN_CONFIG"
+                , "default": {"type": "empty_map"}
+                }
+              , "default": ""
+              }
+            , "'"
+            ]
           }
-        , "'"
-        ]
-      }
-    , { "type": "join"
-      , "$1":
-        [ "HOST_SYSTEM_LIB_DIR='"
-        , { "type": "lookup"
-          , "key": "HOST_SYSTEM_LIB_DIR"
-          , "map":
-            { "type": "var"
-            , "name": "TOOLCHAIN_CONFIG"
-            , "default": {"type": "empty_map"}
-            }
-          , "default": ""
+        , { "type": "join"
+          , "$1":
+            [ "HOST_SYSTEM_LIB_DIR='"
+            , { "type": "lookup"
+              , "key": "HOST_SYSTEM_LIB_DIR"
+              , "map":
+                { "type": "var"
+                , "name": "TOOLCHAIN_CONFIG"
+                , "default": {"type": "empty_map"}
+                }
+              , "default": ""
+              }
+            , "'"
+            ]
+          }
+        , { "type": "join"
+          , "$1":
+            [ "HOST_DYNAMIC_LINKER='"
+            , { "type": "lookup"
+              , "key": "HOST_DYNAMIC_LINKER"
+              , "map":
+                { "type": "var"
+                , "name": "TOOLCHAIN_CONFIG"
+                , "default": {"type": "empty_map"}
+                }
+              , "default": ""
+              }
+            , "'"
+            ]
           }
-        , "'"
+        , "export NJOBS=$(nproc --all 2>/dev/null || echo 1)"
+        , "export MAKEINFO=missing"
+        , "export MAKE=${LOCALBASE}/bin/make"
+        , "export PATH=$(pwd)/binutils/bin:${LOCALBASE}/bin:$PATH"
+        , "export BUILD_ROOT_DIR=${ACTION_DIR}"
+        , "export SHELL=${LOCALBASE}/bin/sh"
+        , "export CONFIG_SHELL=${LOCALBASE}/bin/sh"
+        , "export CXX=no"
+        , "unset LDFLAGS"
+        , "CONF_ARGS="
+        , "if [ -n \"$HOST_SYSTEM_HDR_DIR\" ]; then"
+        , "  CONF_ARGS=\"$CONF_ARGS --with-sysroot=/ --with-native-system-header-dir=$HOST_SYSTEM_HDR_DIR\""
+        , "fi"
+        , "LINK_ARGS="
+        , "if [ -n \"$HOST_SYSTEM_LIB_DIR\" ]; then"
+        , "  export LIBRARY_PATH=\"$HOST_SYSTEM_LIB_DIR\""
+        , "  LINK_ARGS=\"$LINK_ARGS -B$HOST_SYSTEM_LIB_DIR -L$HOST_SYSTEM_LIB_DIR\""
+        , "  LINK_ARGS=\"$LINK_ARGS -Xlinker -rpath -Xlinker $HOST_SYSTEM_LIB_DIR\""
+        , "fi"
+        , "if [ -n \"$HOST_DYNAMIC_LINKER\" ]; then"
+        , "  mv src/gcc/config src/gcc/config.orig"
+        , "  cp -r src/gcc/config.orig src/gcc/config"
+        , "  chmod -R +w src/gcc/config"
+        , "  for h in src/gcc/config/*/*.h; do"
+        , "    grep -q _DYNAMIC_LINKER \"$h\" || continue"
+        , "    sed -i 's|\\(^#define [A-Z]*_DYNAMIC_LINKER[A-Z0-9]* *\"\\).*\"|\\1'$HOST_DYNAMIC_LINKER'\"|g' \"$h\""
+        , "  done"
+        , "fi"
+        , "export LDFLAGS_FOR_TARGET=\"${LINK_ARGS}\""
+        , "if [ -f /lib/ld-musl-$(uname -m).so.1 ]; then"
+        , "  ln -s /lib/ld-musl-$(uname -m).so.1 ${TMPDIR}/ldd"
+        , "  export PATH=$PATH:${TMPDIR}"
+        , "fi"
+        , "cp -r binutils/. ${DESTDIR}/."
+        , "chmod -R +w ${DESTDIR}/*"
         ]
-      }
-    , { "type": "join"
-      , "$1":
-        [ "HOST_DYNAMIC_LINKER='"
-        , { "type": "lookup"
-          , "key": "HOST_DYNAMIC_LINKER"
+      , { "type": "if"
+        , "cond":
+          { "type": "lookup"
+          , "key": "BOOTSTRAP_WRAP_CC"
           , "map":
             { "type": "var"
             , "name": "TOOLCHAIN_CONFIG"
             , "default": {"type": "empty_map"}
             }
-          , "default": ""
           }
-        , "'"
+        , "then":
+          [ "echo \"#!${SHELL}\" > wrapped-cc"
+          , { "type": "join"
+            , "separator": " "
+            , "$1":
+              [ "echo"
+              , { "type": "join_cmd"
+                , "$1":
+                  [ "exec"
+                  , { "type": "join_cmd"
+                    , "$1":
+                      { "type": "++"
+                      , "$1":
+                        [ [ { "type": "lookup"
+                            , "key": "BOOTSTRAP_CC"
+                            , "map":
+                              { "type": "var"
+                              , "name": "TOOLCHAIN_CONFIG"
+                              , "default": {"type": "empty_map"}
+                              }
+                            , "default": "cc"
+                            }
+                          ]
+                        , { "type": "lookup"
+                          , "key": "BOOTSTRAP_CFLAGS"
+                          , "map":
+                            { "type": "var"
+                            , "name": "TOOLCHAIN_CONFIG"
+                            , "default": {"type": "empty_map"}
+                            }
+                          , "default": []
+                          }
+                        ]
+                      }
+                    }
+                  , "\"$@\""
+                  ]
+                }
+              , ">> wrapped-cc"
+              ]
+            }
+          , "chmod 755 wrapped-cc"
+          , "export CC=$(pwd)/wrapped-cc"
+          ]
+        }
+      , [ "cd src"
+        , "for f in $(find . -type f -exec grep -q '#! */bin/sh' {} \\; -print)"
+        , "do"
+        , "  cp $f $f.__work"
+        , "  rm $f"
+        , "  chmod 755 $f.__work"
+        , "  sed -i 's|#! */bin/sh|#!'\"${SHELL}\"'|g' $f.__work"
+        , "  mv $f.__work $f"
+        , "done"
+        , "for f in mpfr/get_patches.c # Source modified in place"
+        , "do"
+        , "  cp $f $f.__work"
+        , "  rm $f"
+        , "  chmod 755 $f.__work"
+        , "  mv $f.__work $f"
+        , "done"
+        , "export check_msgfmt=no   # do not use system's msgfmt, if available"
+        , "${SHELL} ./configure --prefix=/ --enable-languages=c,c++ --disable-multilib --disable-shared --disable-lto --disable-gcov --disable-libmudflap --disable-libgomp --disable-libssp --disable-nls --disable-libitm ${CONF_ARGS} >configure.log 2>&1 || (cat configure.log && exit 1)"
+        , "${MAKE} -j${NJOBS} >build.log 2>&1 || (cat configure.log build.log && exit 1)"
+        , "${MAKE} -j${NJOBS} DESTDIR=${DESTDIR} install-strip >>build.log 2>&1 || (cat configure.log build.log && exit 1)"
+        , "cd ${DESTDIR}"
+        , "for f in $(find . -type f | grep '\\.o$'); do strip -g $f; done"
+        , "for f in $(find . -type f | grep '\\.a$'); do strip -g $f; done"
+        , "GCC_LIBDIR=\"lib/gcc/$(./bin/gcc -dumpmachine)/$(./bin/gcc -dumpfullversion -dumpversion)\""
+        , "mv ${GCC_LIBDIR}/include-fixed ${TMPDIR}/"
+        , "cp -rL ${TMPDIR}/include-fixed ${GCC_LIBDIR}/.   # resolve symlinks"
+        , "cd ${DESTDIR}/bin"
         ]
-      }
-    , "export NJOBS=$(nproc --all 2>/dev/null || echo 1)"
-    , "export MAKEINFO=missing"
-    , "export MAKE=${LOCALBASE}/bin/make"
-    , "export PATH=$(pwd)/binutils/bin:${LOCALBASE}/bin:$PATH"
-    , "export BUILD_ROOT_DIR=${ACTION_DIR}"
-    , "export SHELL=${LOCALBASE}/bin/sh"
-    , "export CONFIG_SHELL=${LOCALBASE}/bin/sh"
-    , "export CXX=no"
-    , "unset LDFLAGS"
-    , "CONF_ARGS="
-    , "if [ -n \"$HOST_SYSTEM_HDR_DIR\" ]; then"
-    , "  CONF_ARGS=\"$CONF_ARGS --with-sysroot=/ --with-native-system-header-dir=$HOST_SYSTEM_HDR_DIR\""
-    , "fi"
-    , "LINK_ARGS="
-    , "if [ -n \"$HOST_SYSTEM_LIB_DIR\" ]; then"
-    , "  export LIBRARY_PATH=\"$HOST_SYSTEM_LIB_DIR\""
-    , "  LINK_ARGS=\"$LINK_ARGS -B$HOST_SYSTEM_LIB_DIR -L$HOST_SYSTEM_LIB_DIR\""
-    , "  LINK_ARGS=\"$LINK_ARGS -Xlinker -rpath -Xlinker $HOST_SYSTEM_LIB_DIR\""
-    , "fi"
-    , "if [ -n \"$HOST_DYNAMIC_LINKER\" ]; then"
-    , "  mv src/gcc/config src/gcc/config.orig"
-    , "  cp -r src/gcc/config.orig src/gcc/config"
-    , "  chmod -R +w src/gcc/config"
-    , "  for h in src/gcc/config/*/*.h; do"
-    , "    grep -q _DYNAMIC_LINKER \"$h\" || continue"
-    , "    sed -i 's|\\(^#define [A-Z]*_DYNAMIC_LINKER[A-Z0-9]* *\"\\).*\"|\\1'$HOST_DYNAMIC_LINKER'\"|g' \"$h\""
-    , "  done"
-    , "fi"
-    , "export LDFLAGS_FOR_TARGET=\"${LINK_ARGS}\""
-    , "if [ -f /lib/ld-musl-$(uname -m).so.1 ]; then"
-    , "  ln -s /lib/ld-musl-$(uname -m).so.1 ${TMPDIR}/ldd"
-    , "  export PATH=$PATH:${TMPDIR}"
-    , "fi"
-    , "cp -r binutils/. ${DESTDIR}/."
-    , "chmod -R +w ${DESTDIR}/*"
-    , "cd src"
-    , "for f in $(find . -type f -exec grep -q '#! */bin/sh' {} \\; -print)"
-    , "do"
-    , "  cp $f $f.__work"
-    , "  rm $f"
-    , "  chmod 755 $f.__work"
-    , "  sed -i 's|#! */bin/sh|#!'\"${SHELL}\"'|g' $f.__work"
-    , "  mv $f.__work $f"
-    , "done"
-    , "for f in mpfr/get_patches.c # Source modified in place"
-    , "do"
-    , "  cp $f $f.__work"
-    , "  rm $f"
-    , "  chmod 755 $f.__work"
-    , "  mv $f.__work $f"
-    , "done"
-    , "export check_msgfmt=no   # do not use system's msgfmt, if available"
-    , "${SHELL} ./configure --prefix=/ --enable-languages=c,c++ --disable-multilib --disable-shared --disable-lto --disable-gcov --disable-libmudflap --disable-libgomp --disable-libssp --disable-nls --disable-libitm ${CONF_ARGS} >configure.log 2>&1 || (cat configure.log && exit 1)"
-    , "${MAKE} -j${NJOBS} >build.log 2>&1 || (cat configure.log build.log && exit 1)"
-    , "${MAKE} -j${NJOBS} DESTDIR=${DESTDIR} install-strip >>build.log 2>&1 || (cat configure.log build.log && exit 1)"
-    , "cd ${DESTDIR}"
-    , "for f in $(find . -type f | grep '\\.o$'); do strip -g $f; done"
-    , "for f in $(find . -type f | grep '\\.a$'); do strip -g $f; done"
-    , "GCC_LIBDIR=\"lib/gcc/$(./bin/gcc -dumpmachine)/$(./bin/gcc -dumpfullversion -dumpversion)\""
-    , "mv ${GCC_LIBDIR}/include-fixed ${TMPDIR}/"
-    , "cp -rL ${TMPDIR}/include-fixed ${GCC_LIBDIR}/.   # resolve symlinks"
-    , "cd ${DESTDIR}/bin"
-    ]
+      ]
+    }
   , "out_dirs": ["."]
   }
 , "link_args.h":