LibGL: Support missing context in `glGetError` and `glGetIntegerv`

In its current state, ScummVM seems to invoke these methods just after
destroying the current GL context. According to the OpenGL spec:

    "Issuing GL commands when the program does not have a current
     context results in undefined behavior, up to and including program
     termination."

Our old behavior was to deref a `nullptr`, which isn't that great. For
now, protect these two methods. If other ports seem to misbehave as
well, we can always expand the check to other methods.

1 files changed, 2 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGL/GLUtils.cpp b/Userland/Libraries/LibGL/GLUtils.cpp
index b580730c72..253d2f4cae 100644
--- a/Userland/Libraries/LibGL/GLUtils.cpp
+++ b/Userland/Libraries/LibGL/GLUtils.cpp
@@ -67,6 +67,7 @@ void glViewport(GLint x, GLint y, GLsizei width, GLsizei height)
 
 GLenum glGetError()
 {
+    VERIFY_CURRENT_CONTEXT_OR_VALUE(GL_NONE);
     return g_gl_context->gl_get_error();
 }
 
@@ -117,6 +118,7 @@ void glGetFloatv(GLenum pname, GLfloat* params)
 
 void glGetIntegerv(GLenum pname, GLint* data)
 {
+    VERIFY_CURRENT_CONTEXT();
     g_gl_context->gl_get_integerv(pname, data);
 }