Fixes this error:
```
drivers\unix\ip_unix.cpp(155): error C2593: 'operator =' is ambiguous
.\core/ustring.h(177): note: could be 'void String::operator =(const CharType *)'
.\core/ustring.h(176): note: or 'void String::operator =(const char *)'
drivers\unix\ip_unix.cpp(155): note: while trying to match the argument list '(String, int)'
```
This fixes an issue that was fixed for gles3 in #31419 but not applied
to gles2. The fix consists of using a constant scale for cube_normal of -1.0
instead of -1000000. It results in broken panorama rendering on the
oculus quest (see https://github.com/GodotVR/godot_oculus_mobile/issues/29)
Although the backup USE_SKELETON_SOFTWARE skinning path is currently used when float texture is not supported, the default skinning path still fails when float texture is supported but GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS is 0, i.e. the device cannot read from texture during vertex shader. This PR adds the logic to activate the SKELETON_SOFTWARE path if either of these cases occur, preventing crashes on devices which have this combination of features.
In 2.1 and 3.0, light_vec could be modified for altering shadow_computations.
But it broke shadows when rotating light. shadow_vec would do the same, but without breaking
shadows in rotated lights if not used.
Add inverse light transformation to shadow vec, so it's not affected when rotating lights;
Added usage define for shadow vec.
For shadow vec working properly when rotating a light, it's needed to multiply it by light_matrix normalized. Added usage define in order to don't do that if shadow_vec not used.
Changed the behaviour of the Linear tonemapping operator to not clamp to [0, 1] range
in the case when KEEP_3D_LINEAR is defined. This allows to render values > 1.0 in
floating point texture targets (via Viewport) for further processing or saving high
dynamic range data into files. This only works when no color conversion is active.
The last remaining ERR_EXPLAIN call is in FreeType code and makes sense as is
(conditionally defines the error message).
There are a few ERR_EXPLAINC calls for C-strings where String is not included
which can stay as is to avoid adding additional _MSGC macros just for that.
Part of #31244.
Condensed some if and ERR statements. Added dots to end of error messages
Couldn't figure out EXPLAINC. These files gave me trouble: core/error_macros.h, core/io/file_access_buffered_fa.h (where is it?),
core/os/memory.cpp,
drivers/png/png_driver_common.cpp,
drivers/xaudio2/audio_driver_xaudio2.cpp (where is it?)
