build-sys: fix crlf-ending C code

On msys2, the shader-to-C script produces bad C:
./ui/shader/texture-blit-vert.h:2:5: error: missing terminating " character [-Werror]

Fix it by changing the line ending from crlf to lf, and convert the
script to Python (qemu build seems perl-free after that).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230110132700.833690-2-marcandre.lureau@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230124180127.1881110-6-alex.bennee@linaro.org>
(cherry picked from commit e2c4012b)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>