chore(cleanup): add Wunknown-pragmas, fix pragma typos

Fix #6035

CMakeLists.txt

@@ -87,6 +87,7 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wstrict-overflow")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wstrict-aliasing")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wunknown-pragmas")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
 
 # avoid timestamps in binary for reproducible builds, not added until GCC 4.9

src/video/cameradevice.cpp

@@ -26,7 +26,7 @@ extern "C" {
 #pragma GCC diagnostic ignored "-Wold-style-cast"
 #include <libavdevice/avdevice.h>
 #include <libavformat/avformat.h>
-#pragma GCC disagnostic pop
+#pragma GCC diagnostic pop
 }
 #include "cameradevice.h"
 #include "src/persistence/settings.h"

src/video/corevideosource.cpp

@@ -22,7 +22,7 @@ extern "C" {
 #pragma GCC diagnostic ignored "-Wold-style-cast"
 #include <libavcodec/avcodec.h>
 #include <libavutil/imgutils.h>
-#pragma GCC disagnostic pop
+#pragma GCC diagnostic pop
 }
 
 #include "corevideosource.h"