Fix warning about functions defined but not used [-Wunused-function]

Fixes the following GCC 5 warnings:
```
core/io/zip_io.h:128:26: warning: 'zlib_filefunc_def zipio_create_io_from_file(FileAccess**)' defined but not used [-Wunused-function]
core/script_debugger_remote.cpp:110:17: warning: 'ObjectID safe_get_instance_id(const Variant&)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:103:12: warning: 'int _socket_create(IP::Type&, int, int)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:45:15: warning: 'size_t _set_sockaddr(sockaddr_storage*, const IP_Address&, int, IP::Type)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:76:15: warning: 'size_t _set_listen_sockaddr(sockaddr_storage*, int, IP::Type, IP_Address)' defined but not used [-Wunused-function]
editor/editor_fonts.cpp:40:24: warning: 'Ref<BitmapFont> make_font(int, int, int, int, const int*, const Ref<Texture>&)' defined but not used [-Wunused-function]
editor/editor_themes.cpp:85:26: warning: 'Ref<StyleBoxFlat> change_border_color(Ref<StyleBoxFlat>, Color)' defined but not used [-Wunused-function]
editor/import/editor_import_collada.cpp:493:13: warning: 'void _generate_normals(const PoolVector<int>&, const PoolVector<Vector3>&, PoolVector<Vector3>&)' defined but not used [-Wunused-function]
editor/import/editor_import_collada.cpp:524:13: warning: 'void _generate_tangents_and_binormals(const PoolVector<int>&, const PoolVector<Vector3>&, const PoolVector<Vector3>&, const PoolVector<Vector3>&, PoolVector<float>&)' defined but not used [-Wunused-function]
editor/pvrtc_compress.cpp:118:13: warning: 'void _compress_etc(Image*)' defined but not used [-Wunused-function]
modules/etc/image_etc.cpp:89:13: warning: 'void _decompress_etc1(Image*)' defined but not used [-Wunused-function]
modules/etc/image_etc.cpp:93:13: warning: 'void _decompress_etc2(Image*)' defined but not used [-Wunused-function]
modules/gdscript/editor/gdscript_highlighter.cpp:46:13: warning: 'bool _is_whitespace(CharType)' defined but not used [-Wunused-function]
scene/2d/cpu_particles_2d.cpp:510:14: warning: 'float rand_from_seed_m1_p1(uint32_t&)' defined but not used [-Wunused-function]
scene/3d/cpu_particles.cpp:474:14: warning: 'float rand_from_seed_m1_p1(uint32_t&)' defined but not used [-Wunused-function]
scene/resources/default_theme/default_theme.cpp:123:20: warning: 'Ref<Shader> make_shader(const char*, const char*, const char*)' defined but not used [-Wunused-function]
scene/resources/default_theme/default_theme.cpp:130:24: warning: 'Ref<BitmapFont> make_font(int, int, int, int, const int*, const Ref<Texture>&)' defined but not used [-Wunused-function]
```

Had to split `core/io/zip_io.h` into header and .cpp file without 'static' keyword.

Not fixed yet (static definition in header used in some files but not all):
```
modules/websocket/lws_helper.h:111:13: warning: 'void _lws_make_protocols(void*, int (*)(lws*, lws_callback_reasons, void*, void*, size_t), PoolVector<String>, _LWSRef**)' defined but not used [-Wunused-function]
```

Also fixed a couple other warnings missed in previous commits.

1 files changed, 3 insertions, 39 deletions

diff --git a/scene/resources/default_theme/default_theme.cpp b/scene/resources/default_theme/default_theme.cpp
index 0dc2ef105b..4de47b2cb0 100644
--- a/scene/resources/default_theme/default_theme.cpp
+++ b/scene/resources/default_theme/default_theme.cpp
@@ -120,41 +120,7 @@ static Ref<Texture> make_icon(T p_src) {
 	return texture;
 }
 
-static Ref<Shader> make_shader(const char *vertex_code, const char *fragment_code, const char *lighting_code) {
-	Ref<Shader> shader = (memnew(Shader()));
-	//shader->set_code(vertex_code, fragment_code, lighting_code);
-
-	return shader;
-}
-
-static Ref<BitmapFont> make_font(int p_height, int p_ascent, int p_valign, int p_charcount, const int *p_chars, const Ref<Texture> &p_texture) {
-
-	Ref<BitmapFont> font(memnew(BitmapFont));
-	font->add_texture(p_texture);
-
-	for (int i = 0; i < p_charcount; i++) {
-
-		const int *c = &p_chars[i * 8];
-
-		int chr = c[0];
-		Rect2 frect;
-		frect.position.x = c[1];
-		frect.position.y = c[2];
-		frect.size.x = c[3];
-		frect.size.y = c[4];
-		Point2 align(c[5], c[6] + p_valign);
-		int advance = c[7];
-
-		font->add_char(chr, 0, frect, align, advance);
-	}
-
-	font->set_height(p_height);
-	font->set_ascent(p_ascent);
-
-	return font;
-}
-
-static Ref<BitmapFont> make_font2(int p_height, int p_ascent, int p_charcount, const int *p_char_rects, int p_kerning_count, const int *p_kernings, int p_w, int p_h, const unsigned char *p_img) {
+static Ref<BitmapFont> make_font(int p_height, int p_ascent, int p_charcount, const int *p_char_rects, int p_kerning_count, const int *p_kernings, int p_w, int p_h, const unsigned char *p_img) {
 
 	Ref<BitmapFont> font(memnew(BitmapFont));
 
@@ -209,8 +175,6 @@ void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const
 
 	tex_cache = memnew(TexCacheMap);
 
-	//Ref<BitmapFont> default_font = make_font(_bi_font_normal_height,_bi_font_normal_ascent,_bi_font_normal_valign,_bi_font_normal_charcount,_bi_font_normal_characters,make_icon(font_normal_png));
-
 	// Font Colors
 
 	Color control_font_color = Color::html("e0e0e0");
@@ -913,9 +877,9 @@ void make_default_theme(bool p_hidpi, Ref<Font> p_font) {
 	if (p_font.is_valid()) {
 		default_font = p_font;
 	} else if (p_hidpi) {
-		default_font = make_font2(_hidpi_font_height, _hidpi_font_ascent, _hidpi_font_charcount, &_hidpi_font_charrects[0][0], _hidpi_font_kerning_pair_count, &_hidpi_font_kerning_pairs[0][0], _hidpi_font_img_width, _hidpi_font_img_height, _hidpi_font_img_data);
+		default_font = make_font(_hidpi_font_height, _hidpi_font_ascent, _hidpi_font_charcount, &_hidpi_font_charrects[0][0], _hidpi_font_kerning_pair_count, &_hidpi_font_kerning_pairs[0][0], _hidpi_font_img_width, _hidpi_font_img_height, _hidpi_font_img_data);
 	} else {
-		default_font = make_font2(_lodpi_font_height, _lodpi_font_ascent, _lodpi_font_charcount, &_lodpi_font_charrects[0][0], _lodpi_font_kerning_pair_count, &_lodpi_font_kerning_pairs[0][0], _lodpi_font_img_width, _lodpi_font_img_height, _lodpi_font_img_data);
+		default_font = make_font(_lodpi_font_height, _lodpi_font_ascent, _lodpi_font_charcount, &_lodpi_font_charrects[0][0], _lodpi_font_kerning_pair_count, &_lodpi_font_kerning_pairs[0][0], _lodpi_font_img_width, _lodpi_font_img_height, _lodpi_font_img_data);
 	}
 	Ref<Font> large_font = default_font;
 	fill_default_theme(t, default_font, large_font, default_icon, default_style, p_hidpi ? 2.0 : 1.0);