CMake: remove ZIG_USE_CCACHE option

Not really useful after old C++ compiler removal, and
zig build has own cache system. If someone still wants it,
`CMAKE_C_COMPILER_LAUNCHER` and `CMAKE_CXX_COMPILER_LAUNCHER` exist.

From CMake docs:

> RULE_LAUNCH_COMPILE
> Note: This property is intended for internal use by ctest(1).
> Projects and developers should use the <LANG>_COMPILER_LAUNCHER
> target properties or the associated CMAKE_<LANG>_COMPILER_LAUNCHER
> variables instead.

Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>

Author: BratishkaErik

CMakeLists.txt

@@ -98,16 +98,6 @@ else()
   set(ZIG_STATIC_CURSES off)
 endif()
 set(ZIG_STATIC_CURSES ${ZIG_STATIC_CURSES} CACHE BOOL "Prefer linking against static curses")
-set(ZIG_USE_CCACHE off CACHE BOOL "Use ccache")
-
-if(ZIG_USE_CCACHE)
-    find_program(CCACHE_PROGRAM ccache)
-    if(CCACHE_PROGRAM)
-      set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "${CCACHE_PROGRAM}")
-    else()
-      message(SEND_ERROR "ccache requested but not found")
-    endif()
-endif()
 
 if (ZIG_SHARED_LLVM AND ZIG_STATIC_LLVM)
     message(SEND_ERROR "-DZIG_SHARED_LLVM and -DZIG_STATIC_LLVM cannot both be enabled simultaneously")