feat: keep original patch headers

apatch

@@ -62,6 +62,14 @@ for patch in $source; do
   fi
 done
 
+header=""
+if [ -f "$patch" ]; then
+  msg "patch exists, trying to extract existing message"
+  # try to extract the original header from the patch
+  patch_start=$(grep -En '^(diff --git|--- )' "$patchpath" | cut -d: -f1 | head -n 1)
+  header="$(head -n $(( patch_start - 1 )) "$patchpath"; echo)"
+fi
+
 (
 	cd "$builddir"
 	git init
@@ -85,10 +93,16 @@ done
 
 	$SHELL
 
-	git add .
-	git diff --cached > "$patchpath"
-	if [ ! -s "$patchpath" ]; then
-	  echo "[*] patch is empty, removing"
-	  rm "$patchpath"
-	fi
+  git add .
+
+  msg "saving patch $patch"
+  echo -n "$header" > "$patchpath"
+  git diff --cached >> "$patchpath"
+
+  if [ ! -s "$patchpath" ]; then
+    msg "patch is empty, removing"
+    rm "$patchpath"
+  fi
+
+  rm -rf .git
 )