Fix CMakeLists.txt for LLVM Windows build

Author: dennisameling

compat/vcbuild/include/sys/utime.h

@@ -22,11 +22,13 @@ struct _utimbuf
 	time_t	modtime;	/* Modification time */
 };
 
+#ifndef	_NO_OLDNAMES
 /* NOTE: Must be the same as _utimbuf above. */
 struct utimbuf
 {
 	time_t	actime;
 	time_t	modtime;
 };
+#endif	/* Not _NO_OLDNAMES */
 
 #endif

compat/vcbuild/include/unistd.h

@@ -6,7 +6,10 @@
 #ifndef _MODE_T_
 #define	_MODE_T_
 typedef unsigned short _mode_t;
+
+#ifndef	_NO_OLDNAMES
 typedef _mode_t	mode_t;
+#endif
 #endif	/* Not _MODE_T_ */
 
 #ifndef _SSIZE_T_

contrib/buildsystems/CMakeLists.txt

@@ -49,9 +49,6 @@ to avoid this, add `-DNO_VCPKG=TRUE` to the command line when configuring.
 ]]
 cmake_minimum_required(VERSION 3.14)
 
-# TODO wrap this in the right conditions (only when using LLVM MinGW Windows)
-add_compile_definitions(_NO_OLDNAMES)
-
 #set the source directory to root of git
 set(CMAKE_SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/../..)
 
@@ -261,7 +258,7 @@ endif()
 
 #Platform Specific
 if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
-	if(CMAKE_C_COMPILER_ID STREQUAL "MSVC" OR CMAKE_C_COMPILER_ID STREQUAL "Clang")
+	if(CMAKE_C_COMPILER_ID STREQUAL "MSVC" OR (NOT CMAKE_GENERATOR STREQUAL "MinGW Makefiles" AND CMAKE_C_COMPILER_ID STREQUAL "Clang"))
 		include_directories(${CMAKE_SOURCE_DIR}/compat/vcbuild/include)
 		add_compile_definitions(_CRT_SECURE_NO_WARNINGS _CRT_NONSTDC_NO_DEPRECATE)
 	endif()