Merge pull request #4676 from dmitrio95/try-fix-windows-build

Try to fix Windows build

CMakeLists.txt

@@ -243,13 +243,18 @@ else (APPLE)
    # Set compiler options for VS2017 toolchain.
    # Note: /D_CRT_SECURE_NO WARNINGS disables warnings when using "non-secure" library functions like sscanf...
       set(CMAKE_CXX_FLAGS                "/MP /DWIN32 /D_WINDOWS /GR /EHsc /D_UNICODE /DUNICODE /D_CRT_SECURE_NO_WARNINGS /execution-charset:utf-8 /source-charset:utf-8")
+      set(CMAKE_C_FLAGS                  "/MP /DWIN32 /D_WINDOWS")
       if (USE_SSE)
          # If USE_SSE is set, enable use of SSE instructions to compiler.
          set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} /arch:SSE")
+         set(CMAKE_C_FLAGS    "${CMAKE_C_FLAGS} /arch:SSE")
       endif (USE_SSE)
       set(CMAKE_CXX_FLAGS_DEBUG          "/MT /permissive- /std:c++14 /W4 /Zi /Ob0 /Od /RTC1")
       set(CMAKE_CXX_FLAGS_RELEASE        "/MT /permissive- /std:c++14 /W4 /O2 /Ob2 /DNDEBUG /DQT_NO_DEBUG /DQT_NO_DEBUG_OUTPUT")
       set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "/MT /permissive- /std:c++14 /W4 /Zi /O2 /Ob1 /DNDEBUG /DQT_NO_DEBUG")
+      set(CMAKE_C_FLAGS_DEBUG            "/MT /W4 /Zi /Ob0 /Od /RTC1")
+      set(CMAKE_C_FLAGS_RELEASE          "/MT /W4 /O2 /Ob2 /DNDEBUG")
+      set(CMAKE_C_FLAGS_RELWITHDEBINFO   "/MT /W4 /Zi /O2 /Ob1 /DNDEBUG")
       set(CMAKE_EXE_LINKER_FLAGS         "/DYNAMICBASE:NO")
    else (MSVC)
       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")

thirdparty/portmidi/CMakeLists.txt

@@ -17,7 +17,7 @@
 #  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #=============================================================================
 
-set(CMAKE_C_FLAGS "-DNEWBUFFER -DPMNULL")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DNEWBUFFER -DPMNULL")
 
 if (APPLE)
   file(GLOB_RECURSE INCS "*.h")