cmake: /std:c99 isn't a valid cl option

Author: kcbanner

CMakeLists.txt

@@ -731,8 +731,8 @@ set(HOST_TARGET_TRIPLE "${HOST_TARGET_ARCH}-${HOST_TARGET_OS}")
 
 if(MSVC)
   set(ZIG_WASM2C_COMPILE_FLAGS "")
-  set(ZIG1_COMPILE_FLAGS "/std:c99 /Os")
-  set(ZIG2_COMPILE_FLAGS "/std:c99 /O0")
+  set(ZIG1_COMPILE_FLAGS "/Os")
+  set(ZIG2_COMPILE_FLAGS "/O0")
   set(ZIG2_LINK_FLAGS "/STACK:16777216")
 else()
   set(ZIG_WASM2C_COMPILE_FLAGS "-std=c99 -O2")