gdb multi-arch v13.2

I took the opportunity to rename the output binaries to have the
`multi-arch-` prefix, because it's really confusing to me to have `gdb`
not be native `gdb` when in a conda environment with this package
installed.

No longer need our ARM backtrace patch, it's now fixed in GDB upstream.

Refreshed the `conda_build_config.yaml` to use the latest conda-build
feedstock version at time of writing:

```bash
❯ curl -sSL https://github.com/conda-forge/conda-forge-pinning-feedstock/raw/main/recipe/conda_build_config.yaml > gdb-multi-arch/conda_build_config.yaml
```

Which is
https://github.com/conda-forge/conda-forge-pinning-feedstock/blob/41ef3139dd637914a18f9609bf3d33a2f4780376/recipe/conda_build_config.yaml
.

This changes the supported + built python targets to:

- 3.8
- 3.9
- 3.10
- 3.11

And include `readelf` in the package (`multi-arch-readelf`), since it
can be pretty handy.

Also, `shfmt` the build script too since I'm in here.

We need a new patch to eliminate some new `warning` messages and an
assert in `set_lang`, which impacts some pathological symbol files. see
`gdb-13.2.patch` for details.

To successfully build this on osx-x64, I needed to symlink a `brew
install m4` copy of the m4 binary into the system tool path so conda
would use it:

```bash
sudo mv /Library/Developer/CommandLineTools/usr/bin/gm4{,.bak}
sudo ln -s /usr/local/Cellar/m4/1.4.19/bin/m4 /Library/Developer/CommandLineTools/usr/bin/gm4
```

The old `gm4` bin doesn't support a `--gnu` flag that newer bison + flex
use during the build.

Lastly, I also added `zstd` as a host + run dep, so it correctly is
`rpath`'d into the binary.

.github/workflows/build.yml

@@ -10,7 +10,9 @@ jobs:
     name: 🛠️ build on ${{ matrix.platform }}
 
     strategy:
-      fail-fast: true
+      # let all jobs run to completion. the linux one may succeed when the mac
+      # fails (taking a completely random example scenario 😑)
+      fail-fast: false
       matrix:
         platform: [ubuntu-20.04, macos-11, macos-13-xlarge] #  windows-2022] windows is a bit sad :'(
     runs-on: ${{ matrix.platform }}

README.md

@@ -21,7 +21,7 @@ To build any of the following packages (macOS and Linux Ubuntu 18.04 tested):
 
 ```bash
 # Create build environment
-$ conda create -n build conda-build anaconda-client
+$ conda create --name build --file environment.yml
 $ conda activate build
 
 # Build specific recipe
@@ -116,7 +116,7 @@ and download the "packages" artifact.
 Unzip the packages.zip and then run:
 
 ```shell
-PACKAGE=<package_name> anaconda upload **/$PACKAGE*.tar.bz2 --user memfault
+PACKAGE=<package_name>; anaconda upload **/$PACKAGE*.conda --user memfault
 ```
 
 > Note: [Github actions cannot be run on Apple ARM VMs](https://github.com/actions/virtual-environments/issues/2187)

gdb-multi-arch/build.sh

@@ -12,7 +12,7 @@ export REAL_TARGET_PREFIX="${PREFIX}/${REAL_TARGET}"
 export CPPFLAGS="$CPPFLAGS -fcommon -I$PREFIX/include -Wno-constant-logical-operand"
 export CFLAGS="$CFLAGS -Wno-constant-logical-operand -Wno-format-nonliteral -Wno-self-assign"
 
-if [ `uname` == Darwin ]; then
+if [ $(uname) == Darwin ]; then
   EXTRA_CONFIGURE_FLAGS=""
 else
   EXTRA_CONFIGURE_FLAGS="--with-debuginfod"
@@ -21,27 +21,27 @@ fi
 # Setting /usr/lib/debug as debug dir makes it possible to debug the system's
 # python on most Linux distributions
 ./configure \
-    --prefix="$FAKE_TARGET_PREFIX" \
-    --target="$FAKE_TARGET" \
-    --enable-targets=all \
-    --with-separate-debug-dir="${FAKE_TARGET_PREFIX}/lib/debug:/usr/lib/debug" \
-    --with-lzma \
-    --with-expat \
-    --with-libexpat-prefix="$PREFIX" \
-    --with-libiconv-prefix="$PREFIX" \
-    --without-guile \
-    --without-libunwind-ia64 \
-    --with-zlib \
-    --without-babeltrace \
-    --with-python="$PREFIX" \
-    $EXTRA_CONFIGURE_FLAGS \
-    --disable-ld \
-    --disable-gprof \
-    --disable-gas \
-    --disable-sim \
-    --disable-gold \
-    --enable-64-bit-bfd
-make
+  --prefix="$FAKE_TARGET_PREFIX" \
+  --target="$FAKE_TARGET" \
+  --enable-targets=all \
+  --with-separate-debug-dir="${FAKE_TARGET_PREFIX}/lib/debug:/usr/lib/debug" \
+  --with-lzma \
+  --with-expat \
+  --with-libexpat-prefix="$PREFIX" \
+  --with-libiconv-prefix="$PREFIX" \
+  --without-guile \
+  --without-libunwind-ia64 \
+  --with-zlib \
+  --without-babeltrace \
+  --with-python="$PREFIX" \
+  $EXTRA_CONFIGURE_FLAGS \
+  --disable-ld \
+  --disable-gprof \
+  --disable-gas \
+  --disable-sim \
+  --disable-gold \
+  --enable-64-bit-bfd
+make -j${CPU_COUNT}
 make install
 
 # Move from the fake to real directory
@@ -50,26 +50,38 @@ mv "${FAKE_TARGET_PREFIX}" "${REAL_TARGET_PREFIX}"
 # Enable matching with ! (not) bash operator
 shopt -s extglob
 
-# Delete every binary except addr2line, gdb, gdb-add-index, objcopy, objdump, and size.
+# Delete most of the generated binaries like ld etc. Save gdb and its
+# dependencies, and a few other very useful ones.
 pushd "${REAL_TARGET_PREFIX}"/bin/
-    rm !(arm-elf-linux-addr2line|arm-elf-linux-gdb|arm-elf-linux-gdb-add-index|arm-elf-linux-objdump|arm-elf-linux-objcopy|arm-elf-linux-size|arm-elf-linux-strings)
-    mv arm-elf-linux-addr2line addr2line
-    mv arm-elf-linux-gdb gdb
-    mv arm-elf-linux-gdb-add-index gdb-add-index
-    mv arm-elf-linux-objcopy objcopy
-    mv arm-elf-linux-objdump objdump
-    mv arm-elf-linux-size size
-    mv arm-elf-linux-strings strings
-    strip addr2line
-    strip gdb
-    strip objdump
-    strip objcopy
-    strip size
-    strip strings
-popd
+# array
+bins_to_keep=(
+  "addr2line"
+  "gdb"
+  "gdb-add-index"
+  "objcopy"
+  "objdump"
+  "readelf"
+  "size"
+  "strings"
+)
+# prefix with the original target name prefix
+prefix_bins_to_keep="${bins_to_keep[*]/#/${FAKE_TARGET}-}"
+# get all non-matching globs (thanks to extglob), for deletion
+antiglob="!(${prefix_bins_to_keep// /|})"
+rm ${antiglob}
+
+# Rename the binaries to the real target name prefix
+for _x in "${bins_to_keep[@]}"; do
+  mv "${FAKE_TARGET}-${_x}" "${REAL_TARGET}-${_x}"
 
+  # don't strip "gdb-add-index", it's a shell script
+  if [[ ! "${REAL_TARGET}-${_x}" =~ "gdb-add-index" ]]; then
+    strip "${REAL_TARGET}-${_x}"
+  fi
+done
+popd
 
 # Symlink every binary from the build into /bin
 pushd "${PREFIX}"/bin
-    ln -s "${REAL_TARGET_PREFIX}"/bin/* ./
+ln -s "${REAL_TARGET_PREFIX}"/bin/* ./
 popd