Added p4merge as mergetool in git config (only if OS is windows).

dot_gitconfig.tmpl

@@ -63,8 +63,26 @@
 [push]
     # default = matching
     default = simple # safer option, push only current branch
+[pull]
+    ff = only
+
+{{ if eq .chezmoi.os "windows" -}}
 [merge]
     tool = p4merge
     ff = false
-[pull]
-	ff = only
+
+[mergetool "p4merge"]
+    path = "C:\\Program Files\\Perforce\\p4merge.exe"
+    cmd = p4merge $BASE $LOCAL $REMOTE $MERGED
+    keepBackup = false
+
+[difftool "p4merge"]
+    external = p4merge $LOCAL $REMOTE
+
+[difftool "winmerge"]
+    cmd = "'c:/PortableApps/PortableApps/WinMergePortable/App/WinMerge/WinMergeU'" -e "$LOCAL" "$REMOTE"
+
+{{ end -}}
+
+[http]
+    # proxy = http://host:port