### Problem description
#### Problem 1
In borderless mode ImHex disables the standard macOS titlebar rendering
and input processing. As a result double clicking the titlebar does not
trigger the native macOS behavior set in `System Settings -> Desktop &
Dock -> Double-click a window's title bar to [Zoom/Minimize/Do
nothing]`.
#### Problem 2
The ImHex window shows up as blank/transparent when de-minimizing it
from the dock.
#### Problem 3
Widgets experience ghost hover inputs from the past position of the
cursor during live resizing.
### Implementation description
ImGui elements consume input events in the order they are drawn. As a
result by "drawing" an `InvisibleButton` over the content area of the
titlebar we can catch unprocessed clicks in the titlebar area.
Connecting this button's double clicks to the native window is then a
trivial endeavour.
The blank windows was caused by the rendering stack clearing the GL
buffer, but proceeding to draw nothing in it. I have short circuited
this path.
Ghost hover inputs were squelched by consistently moving the ImGui
cursor to `0, 0` during a live resize. The OS will dispatch a cursor
positioning event once the resizing ends, restoring normal behavior.
### Screenshots
N/A
### Additional things
N/A
---------
Co-authored-by: Nik <werwolv98@gmail.com>
* build: Experimentally switch to gcc on macOS
* build: Corrected gcc paths
* build: Enable objective c support on macOS
* build: Enable ObjC and ObjC++ on macOS
* build: Add ObjC and ObjC++ flags
* build: Try compiling objc with clang
* build: Remove invalid flags again
* fix: Let's not include objc headers in C++ code
* sys: Move macos utils code to its own file
* fix: Missing unistd include on mac
* sys: Removed loader script stuff since it's currently unused and broken
* fix: Missing include
* fix: Another missing include
* fix: CFURLCreateWithBytes wants a pointer to mutable data
* fix: Try disabling name mangling of ObjC functions
* sys: Move macos utils declarations to its own header file
* fix: C Linkage
* fix: Move objc function prototypes to C++ headers
* fix: More missing includes
* fix: Warning error
* sys: Call ObjC with C ABI instead of trying to use C++
* build: Update libraries
* sys: Fixed build errors
* sys: No const correctness I guess
* sys: Fixed prototypes
* sys: This is C now
* sys: More nullptr -> NULL
* sys: Fix crash on exit
* sys: Try using proper std concepts instead of custom ones
* sys: Replaced another hex::is_signed
* build: Upgrade to gcc 12 and MacOS Monterey
* build: Fixed MacOS runner name
* build: Cache correct ccache folder on macOS
