Cleanup: suppress 'address' warnings for ./extern/glew

Also add comments noting why some warnings shouldn't be added to
strict-flags.

CMakeLists.txt

@@ -937,7 +937,10 @@ set(PLATFORM_CFLAGS)
 set(C_WARNINGS)
 set(CXX_WARNINGS)
 
-# for gcc -Wno-blah-blah
+# NOTE: These flags are intended for situations where where it's impractical to
+# suppress warnings by modifying the code or for code which is maintained externally.
+# For GCC this typically means adding `-Wno-*` arguments to negate warnings
+# that are useful in the general case.
 set(C_REMOVE_STRICT_FLAGS)
 set(CXX_REMOVE_STRICT_FLAGS)
 
@@ -1617,6 +1620,18 @@ if(CMAKE_COMPILER_IS_GNUCC)
     ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_IMPLICIT_FALLTHROUGH -Wimplicit-fallthrough=5)
   endif()
 
+
+  #----------------------
+  # Suppress Strict Flags
+  #
+  # Exclude the following warnings from this list:
+  # - `-Wno-address`:
+  #   This can give useful hints that point to bugs/misleading logic.
+  # - `-Wno-strict-prototypes`:
+  #   No need to support older C-style prototypes.
+  #
+  # If code in `./extern/` needs to suppress these flags that can be done on a case-by-case basis.
+
   # flags to undo strict flags
   ADD_CHECK_C_COMPILER_FLAG(C_REMOVE_STRICT_FLAGS C_WARN_NO_DEPRECATED_DECLARATIONS -Wno-deprecated-declarations)
   ADD_CHECK_C_COMPILER_FLAG(C_REMOVE_STRICT_FLAGS C_WARN_NO_UNUSED_PARAMETER        -Wno-unused-parameter)
@@ -1672,6 +1687,9 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
   # ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_UNUSED_MACROS      -Wunused-macros)
   # ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_UNUSED_MACROS          -Wunused-macros)
 
+  #----------------------
+  # Suppress Strict Flags
+
   # flags to undo strict flags
   ADD_CHECK_C_COMPILER_FLAG(C_REMOVE_STRICT_FLAGS C_WARN_NO_UNUSED_PARAMETER -Wno-unused-parameter)
   ADD_CHECK_C_COMPILER_FLAG(C_REMOVE_STRICT_FLAGS C_WARN_NO_UNUSED_VARIABLE  -Wno-unused-variable)

extern/glew/CMakeLists.txt

@@ -7,6 +7,11 @@ if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
     "-Wno-strict-prototypes"
   )
 endif()
+if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "12.1"))
+  add_c_flag(
+    "-Wno-address"
+  )
+endif()
 
 # MSVC's inliner is not having a happy time with glewIsSupported
 # causing this to be one of the most expensive things to build