[Git] Create git shell driver for macOS

Co-authored-by: Elliot Saba <[email protected]>

G/Git/build_tarballs.jl

@@ -59,6 +59,8 @@ make install INSTALL_SYMLINKS="yes, please"
 # environment variable `DYLD_FALLBACK_LIBRARY_PATH` is reset.  We work around this
 # limitation by re-exporting `DYLD_FALLBACK_LIBRARY_PATH` through another environment
 # variable called `JLL_DYLD_FALLBACK_LIBRARY_PATH` which won't be reset by SIP.
+# Read more about the issue and the hacks we apply here at
+# <https://github.com/JuliaVersionControl/Git.jl/issues/40>.
 if [[ "${target}" == *-apple-* ]]; then
     for file in $(grep -l -r '^#!/bin/sh' "${prefix}"); do
         if [[ $(basename "${file}") == git* ]]; then
@@ -70,6 +72,20 @@ if [[ "${target}" == *-apple-* ]]; then
             sed -i -e 's?^#!/usr/bin/perl?#!/usr/bin/perl\n$ENV{'DYLD_FALLBACK_LIBRARY_PATH'} = $ENV{'JLL_DYLD_FALLBACK_LIBRARY_PATH'};?' "${file}"
         fi
     done
+
+    # Rename the `git` binary executable
+    mv "${bindir}/git" "${bindir}/_git"
+
+    # Create a shell driver called `git` which re-exports `DYLD_FALLBACK_LIBRARY_PATH` for us
+    cat > "${bindir}/git" << 'EOF'
+#!/bin/bash
+
+SCRIPT_DIR=$( cd -- "$( dirname -- $(readlink -f "${BASH_SOURCE[0]}") )" &> /dev/null && pwd )
+export DYLD_FALLBACK_LIBRARY_PATH="${JLL_DYLD_FALLBACK_LIBRARY_PATH}"
+exec -a "${BASH_SOURCE[0]}" "${SCRIPT_DIR}/_git" "$@"
+EOF
+
+    chmod +x "${bindir}/git"
 fi
 """