[gcc r14-6762] contrib: add git gcc-style alias

[Jason Merrill]

https://gcc.gnu.org/g:af3fc0306948f5b6abecad8453938c5bedb976fc

commit r14-6762-gaf3fc0306948f5b6abecad8453938c5bedb976fc
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Dec 11 19:38:32 2023 -0500

    contrib: add git gcc-style alias
    
    I thought it could be easier to use check_GNU_style.py.  With this alias,
    'git gcc-style' will take a git revision as argument instead of a file, or
    check HEAD if no argument is given.
    
    contrib/ChangeLog:
    
            * gcc-git-customization.sh: Add git gcc-style alias.

Diff:
---
 contrib/gcc-git-customization.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/contrib/gcc-git-customization.sh b/contrib/gcc-git-customization.sh
index 2e173e859d7..54bd35ea1aa 100755
--- a/contrib/gcc-git-customization.sh
+++ b/contrib/gcc-git-customization.sh
@@ -30,6 +30,11 @@ git config alias.gcc-backport '!f() { "`git rev-parse --show-toplevel`/contrib/g
 git config alias.gcc-fix-changelog '!f() { "`git rev-parse --show-toplevel`/contrib/git-fix-changelog.py" $@; } ; f'
 git config alias.gcc-mklog '!f() { "`git rev-parse --show-toplevel`/contrib/mklog.py" $@; } ; f'
 git config alias.gcc-commit-mklog '!f() { "`git rev-parse --show-toplevel`/contrib/git-commit-mklog.py" "$@"; }; f'
+git config alias.gcc-style '!f() {
+    check=`git rev-parse --show-toplevel`/contrib/check_GNU_style.py;
+    arg=; if [ $# -ge 1 ] && [ "$1" != "-f" ]; then arg="$1"; shift;
+    elif [ $# -eq 3 ]; then arg="$3"; set -- "$1" "$2"; fi
+    git show $arg | $check "$@" -; }; f'
 
 # Make diff on MD files use "(define" as a function marker.
 # Use this in conjunction with a .gitattributes file containing