Update ExternalAntlr4Cpp.cmake

Author: kmfrank

cpp/buildAntlr4/ExternalAntlr4Cpp.cmake

@@ -79,24 +79,44 @@ if(NOT DEFINED ANTLR4_WITH_STATIC_CRT)
 endif()
 
 if(ANTLR4_ZIP_REPOSITORY)
-  ExternalProject_Add(
-      antlr4_runtime
-      PREFIX antlr4_runtime
-      URL ${ANTLR4_ZIP_REPOSITORY}
-      DOWNLOAD_DIR ${CMAKE_CURRENT_BINARY_DIR}
-      if(MINGW) PATCH_COMMAND "/usr/bin/patch" "-p1" "<" "${ANTLR4_MINGW_PATCH}"
-      BUILD_COMMAND ""
-      BUILD_IN_SOURCE 1
-      SOURCE_DIR ${ANTLR4_ROOT}
-      SOURCE_SUBDIR runtime/Cpp
-      CMAKE_CACHE_ARGS
-          -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
-          -DWITH_STATIC_CRT:BOOL=${ANTLR4_WITH_STATIC_CRT}
-          -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
-          # -DCMAKE_CXX_STANDARD:STRING=17 # if desired, compile the runtime with a different C++ standard
-          # -DCMAKE_CXX_STANDARD:STRING=${CMAKE_CXX_STANDARD} # alternatively, compile the runtime with the same C++ standard as the outer project
-      INSTALL_COMMAND ""
-      EXCLUDE_FROM_ALL 1)
+  if(MINGW)
+    ExternalProject_Add(
+        antlr4_runtime
+        PREFIX antlr4_runtime
+        URL ${ANTLR4_ZIP_REPOSITORY}
+        DOWNLOAD_DIR ${CMAKE_CURRENT_BINARY_DIR}
+        PATCH_COMMAND "/usr/bin/patch" "-p1" "<" "${ANTLR4_MINGW_PATCH}"
+        BUILD_COMMAND ""
+        BUILD_IN_SOURCE 1
+        SOURCE_DIR ${ANTLR4_ROOT}
+        SOURCE_SUBDIR runtime/Cpp
+        CMAKE_CACHE_ARGS
+            -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+            -DWITH_STATIC_CRT:BOOL=${ANTLR4_WITH_STATIC_CRT}
+            -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
+            # -DCMAKE_CXX_STANDARD:STRING=17 # if desired, compile the runtime with a different C++ standard
+            # -DCMAKE_CXX_STANDARD:STRING=${CMAKE_CXX_STANDARD} # alternatively, compile the runtime with the same C++ standard as the outer project
+        INSTALL_COMMAND ""
+        EXCLUDE_FROM_ALL 1)
+  else()
+    ExternalProject_Add(
+        antlr4_runtime
+        PREFIX antlr4_runtime
+        URL ${ANTLR4_ZIP_REPOSITORY}
+        DOWNLOAD_DIR ${CMAKE_CURRENT_BINARY_DIR}
+        BUILD_COMMAND ""
+        BUILD_IN_SOURCE 1
+        SOURCE_DIR ${ANTLR4_ROOT}
+        SOURCE_SUBDIR runtime/Cpp
+        CMAKE_CACHE_ARGS
+            -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+            -DWITH_STATIC_CRT:BOOL=${ANTLR4_WITH_STATIC_CRT}
+            -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
+            # -DCMAKE_CXX_STANDARD:STRING=17 # if desired, compile the runtime with a different C++ standard
+            # -DCMAKE_CXX_STANDARD:STRING=${CMAKE_CXX_STANDARD} # alternatively, compile the runtime with the same C++ standard as the outer project
+        INSTALL_COMMAND ""
+        EXCLUDE_FROM_ALL 1)
+  endif()
 else()
   ExternalProject_Add(
       antlr4_runtime