Add a .gitignore file. It's a copy of .hgignore with one line removed.

.gitignore

@@ -1,3 +1,82 @@
+# This is .gitignore
+
+# Unixen: object and executable files.
+*.o
+src/vim
+src/xxd/xxd
+src/auto/if_perl.c
+src/tags
+
+# We do need src/auto/configure.
+src/auto/config.aap
+src/auto/config.cache
+src/auto/config.h
+src/auto/config.log
+src/auto/config.mk
+src/auto/config.status
+src/auto/configure.aap
+src/auto/osdef.h
+src/auto/link.log
+src/auto/link.sed
+src/auto/pathdef.c
+
+# Windows
+*.exe
+*.idb
+*.manifest
+*.exp
+*.obj
+*.pdb
+*.ilk
+*.sln
+*.suo
+*.res
+*.RES
+src/if_perl.c
+src/pathdef.c
+src/Obj*/pathdef.c
+gvimext.dll
+gvimext.lib
+
+# Borland C++
+bcc.cfg
+*.ilc
+*.ild
+*.ilf
+*.ils
+*.map
+*.tds
+
+# NetBeans
+nbproject/*
+
+# Mac OSX
+src/xxd/xxd.dSYM
+
+# All platforms
+*.rej
+*.orig
+*.mo
+*.swp
+*~
+*.pyc
+*.log
+src/po/vim.pot
+
+# Generated by "make test"
+src/po/*.ck
+src/testdir/mbyte.vim
+src/testdir/mzscheme.vim
+src/testdir/lua.vim
+src/testdir/small.vim
+src/testdir/tiny.vim
+src/testdir/test*.out
+src/testdir/test*.failed
+src/testdir/test.log
+src/testdir/dostmp/*
+src/memfile_test
+
+# From MacVim
 .*.swp
 .DS_Store
 src/MacVim/MacVim.xcodeproj/*.mode1