autotools: include meson build files in tarball

This adds the meson.build, meson_options.txt, and a few scripts that are
used exclusively by the meson build.

v2: - Remove accidentally included changes needed to test make dist with
      LLVM > 3.9

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/mapi/Makefile.am

@@ -36,7 +36,12 @@ EXTRA_DIST = \
 	mapi_abi.py \
 	glapi/SConscript \
 	glapi/registry/gl.xml \
-	shared-glapi/SConscript
+	shared-glapi/SConscript \
+	es1api/meson.build \
+	es2api/meson.build \
+	glapi/meson.build \
+	shared-glapi/meson.build \
+	meson.build
 
 AM_CFLAGS = \
 	$(PTHREAD_CFLAGS) \

src/mapi/glapi/gen/Makefile.am

@@ -90,7 +90,8 @@ EXTRA_DIST= \
 	remap_helper.py \
 	static_data.py \
 	SConscript \
-	gl_API.dtd
+	gl_API.dtd \
+	meson.build
 
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