Update GCC to 4.9.2

Update the GCC compiler to the 4.9.2 version.  It turns out that a C++
compiler is required to build the latest GCC releases, so build one in
stages 1 and 2 as well.

The updated list of GCC configuration options that either don't work in
a cross compiler or are not needed in a temporary compiler, were based
on the latest instructions from Linux From Scratch.

The inclusion of /lib64 in the lib path for the stage 1 linker is an
attempt to turn things more robust rather than to just symlink in /lib
stuff that ends up installed in /lib64 (as it is already being done for
libgcc_s.so).  Ideally, we should configure every chunk to install to
/lib, however GCC seems to not honour the `--with-libdir` configuration
flag.

With this version of GCC, it looks like a sysroot needs to be given at
configure time so that `--with-native-system-header-dir` does what it
claims to do.  Unfortunately, this has the side effect of making GCC not
passing to the linker the linker sysroot flag: `-Wl,--sysroot=$SYSROOT`.
The workaround is to modify LDFLAGS to give a sysroot directly to GCC,
`--sysroot=$SYSROOT`, which will then be further passed down to the
linker.

As the newest version of GCC finds more warnings than the previous one,
`-Werror` was disabled for the coreutils, GDB and Syslinux projects.
Syslinux's Makefile had to be patched, as it is not possible to disable
`-Werror` for all targets through the NO_WERROR variable.

The hack to handle libgcc_eh being required during eglibc's build was
removed, as it doesn't seem to be the case anymore.

1 files changed, 36 insertions, 0 deletions

diff --git a/strata/build-essential/stage2-libstdc++.morph b/strata/build-essential/stage2-libstdc++.morph
new file mode 100644
index 00000000..3d89ad85
--- /dev/null
+++ b/strata/build-essential/stage2-libstdc++.morph
@@ -0,0 +1,36 @@
+name: stage2-libstdc++
+kind: chunk
+configure-commands:
+- mkdir o
+
+# Configure flag notes:
+#  1. The thread C++ library cannot be built, as the thread C library
+#     was not build in stage1-gcc.
+#  2. Prevents the installation of precompiled include files, which are
+#     not needed at this stage.
+#  3. From LFS: the header location of C++ needs to be explicitly given
+#     as we are running the configure script from the top-level
+#     directory.
+- |
+  export STAGE2_SYSROOT="$(dirname $(pwd))"
+  # -fPIC must be given, otherwise it will not be possible to create
+  # shared libraries linked to libstdc++
+  export CPPFLAGS="--sysroot=$STAGE2_SYSROOT -fPIC"
+  export LDFLAGS="--sysroot=$STAGE2_SYSROOT"
+  cd o && ../libstdc++-v3/configure                           \
+            --build=$(sh ../config.guess)                     \
+            --host="$TARGET_STAGE1"                           \
+            --target="$TARGET_STAGE1"                         \
+            --prefix="$PREFIX"                                \
+            --disable-nls                                     \
+            --disable-shared                                  \
+            --disable-multilib                                \
+    `# [1]` --disable-libstdcxx-threads                       \
+    `# [2]` --disable-libstdcxx-pch                           \
+    `# [3]` --with-gxx-include-dir=/tools/"$TARGET_STAGE1"/include/c++/4.9.2
+
+build-commands:
+- cd o && make
+
+install-commands:
+- cd o && make DESTDIR="$DESTDIR" install