Cleanup: use term suppress instead of repress

Also check MSVC instead of WIN32, for setting MSVC flags.

extern/bullet2/CMakeLists.txt

@@ -415,9 +415,9 @@ if(CMAKE_COMPILER_IS_GNUCXX)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fpermissive")
 endif()
 
-if(WIN32)
+if(MSVC)
   # bullet is responsible for quite a few silly warnings
-  # repress all of them. Not great, but they really needed
+  # suppress all of them. Not great, but they really needed
   # to sort that out themselves.
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W0")
 endif()

extern/glog/CMakeLists.txt

@@ -77,9 +77,11 @@ if(WIN32)
   list(APPEND INC
     src/windows
   )
-  # Repress warning about google::LogMessageFatal::~LogMessageFatal
-  # not returning.
-  add_definitions("/wd4722")
+  if(MSVC)
+    # Suppress warning about google::LogMessageFatal::~LogMessageFatal
+    # not returning.
+    add_definitions("/wd4722")
+  endif()
 else()
   list(APPEND INC
     include