[repos] nanosvg: convert to submodule

This is fine now that nanosvg can be compiled with -Wstrict-prototypes
without warning.

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "repos/wayland-protocols"]
 	path = repos/wayland-protocols
 	url = https://gitlab.freedesktop.org/wayland/wayland-protocols.git
+[submodule "repos/nanosvg"]
+	path = repos/nanosvg
+	url = https://github.com/memononen/nanosvg.git

repos/nanosvg

@@ -0,0 +1 @@
+Subproject commit 64d59e4d53308104181c6a7ad71fbf423f71910f

repos/nanosvg/.gitignore

@@ -1,31 +0,0 @@
-## Compiled source #
-*.com
-*.class
-*.dll
-*.exe
-*.o
-*.so
-test
-
-## Logs and databases #
-*.log
-*.sql
-*.sqlite
-
-## OS generated files #
-.DS_Store
-.DS_Store?
-._*
-.Spotlight-V100
-.Trashes
-ehthumbs.db
-Thumbs.db
-
-## Build dir
-build/*
-
-## Stuff in example
-example/_*
-
-## xcode specific
-*xcuserdata*

repos/nanosvg/LICENSE.txt

@@ -1,18 +0,0 @@
-Copyright (c) 2013-14 Mikko Mononen memon@inside.org
-
-This software is provided 'as-is', without any express or implied
-warranty.  In no event will the authors be held liable for any damages
-arising from the use of this software.
-
-Permission is granted to anyone to use this software for any purpose,
-including commercial applications, and to alter it and redistribute it
-freely, subject to the following restrictions:
-
-1. The origin of this software must not be misrepresented; you must not
-claim that you wrote the original software. If you use this software
-in a product, an acknowledgment in the product documentation would be
-appreciated but is not required.
-2. Altered source versions must be plainly marked as such, and must not be
-misrepresented as being the original software.
-3. This notice may not be removed or altered from any source distribution.
-