Windows build errors on filter descriptors

[DanBrink91]

Attempting to build on windows, here's me trying to make deps:

C:\Dev\permafrost-engine>make deps PLAT=WINDOWS
mkdir -p ./lib
make -C ./deps/GLEW extensions
make[1]: Entering directory `C:/Dev/permafrost-engine/deps/GLEW'
make -C auto
make[2]: Entering directory `C:/Dev/permafrost-engine/deps/GLEW/auto'
--------------------------------------------------------------------
OpenGL descriptors
--------------------------------------------------------------------
rm -rf extensions/gl
cp -r glfixes/gl/specs/ANGLE OpenGL-Registry/extensions
cp -r glfixes/gl/specs/REGAL OpenGL-Registry/extensions
bin/update_ext.sh extensions/gl OpenGL-Registry/extensions blacklist
FIND: Parameter format not correct
--------------------------------------------------------------------
WGL descriptors
--------------------------------------------------------------------
rm -f extensions/gl/WGL_*
python bin/parse_xml.py OpenGL-Registry/xml/wgl.xml --api wgl --extensions extensions/gl
Found 298 enums, 146 commands, 1 features and 57 extensions.
--------------------------------------------------------------------
GLX descriptors
--------------------------------------------------------------------
rm -f extensions/gl/GLX_*
python bin/parse_xml.py OpenGL-Registry/xml/glx.xml --api glx --extensions extensions/gl
Found 294 enums, 134 commands, 5 features and 67 extensions.
--------------------------------------------------------------------
EGL descriptors
--------------------------------------------------------------------
python bin/parse_xml.py EGL-Registry/api/egl.xml --api egl --extensions extensions/gl
Found 655 enums, 154 commands, 6 features and 150 extensions.
--------------------------------------------------------------------
filter descriptors
--------------------------------------------------------------------
bin/filter_gl_ext.sh extensions/gl
grep: extensions/gl/GL_NV_texture_compression_vtc: No such file or directory
make[2]: *** [extensions/gl/.dummy] Error 2
make[2]: Leaving directory `C:/Dev/permafrost-engine/deps/GLEW/auto'
make[1]: *** [extensions] Error 2
make[1]: Leaving directory `C:/Dev/permafrost-engine/deps/GLEW'
make: *** [lib/glew32.dll] Error 2

[eduard-permyakov]

I'll take a closer look at it. Cloning GLEW from here (http://glew.sourceforge.net/) or the github mirror and building the DLL separately should be a good enough workaround for the time being.