[MinGW] remove obsolete flag

See https://github.com/msys2/MINGW-packages/issues/5321

kotlin-native/konan/konan.properties

@@ -703,7 +703,7 @@ clangNooptFlags.mingw_x64 = -O1
 linkerNoDebugFlags.mingw_x64 = -Wl,-S
 linkerDynamicFlags.mingw_x64 = -shared
 linkerKonanFlags.mingw_x64 =-static-libgcc -static-libstdc++ \
-  -Xclang -flto-visibility-public-std -Wl,--dynamicbase \
+  -Wl,--dynamicbase \
   -Wl,-Bstatic,--whole-archive -lwinpthread -Wl,--no-whole-archive,-Bdynamic \
   -Wl,--defsym,__cxa_demangle=Konan_cxa_demangle
 linkerOptimizationFlags.mingw_x64 = -Wl,--gc-sections
@@ -741,7 +741,7 @@ clangNooptFlags.mingw_x86 = -O1
 linkerNoDebugFlags.mingw_x86 = -Wl,-S
 linkerDynamicFlags.mingw_x86 = -shared
 linkerKonanFlags.mingw_x86 = -static-libgcc -static-libstdc++ \
-  -Xclang -flto-visibility-public-std -Wl,--dynamicbase \
+  -Wl,--dynamicbase \
   -Wl,-Bstatic,--whole-archive -lwinpthread -Wl,--no-whole-archive,-Bdynamic \
   -Wl,--defsym,___cxa_demangle=_Konan_cxa_demangle
 mimallocLinkerDependencies.mingw_x86 = -lbcrypt

kotlin-native/shared/src/main/kotlin/org/jetbrains/kotlin/konan/target/ClangArgs.kt

@@ -76,7 +76,7 @@ class ClangArgs(private val configurables: Configurables) : Configurables by con
             }
 
     private val specificClangArgs: List<String> = when (target) {
-        KonanTarget.LINUX_X64 -> listOf()
+        KonanTarget.LINUX_X64 -> emptyList()
 
         KonanTarget.LINUX_ARM32_HFP -> listOf(
                 "-mfpu=vfp", "-mfloat-abi=hard",
@@ -100,9 +100,7 @@ class ClangArgs(private val configurables: Configurables) : Configurables by con
                 "-I$absoluteTargetSysRoot/usr/include/c++/4.9.4/mipsel-unknown-linux-gnu"
         )
 
-        KonanTarget.MINGW_X64, KonanTarget.MINGW_X86 -> listOf(
-                "-Xclang", "-flto-visibility-public-std"
-        )
+        KonanTarget.MINGW_X64, KonanTarget.MINGW_X86 -> emptyList()
 
         KonanTarget.MACOS_X64 -> listOf(
                 "-mmacosx-version-min=$osVersionMin"