--- a/ChangeLog	Sat Oct 01 16:14:00 2022 +0200
+++ b/ChangeLog	Sun Oct 02 13:58:33 2022 +0200
@@ -16,6 +16,8 @@
   o added macros to feature test implementation for aggregate-by-value and syscall support
   o windows/x64/masm directives added to specify how stack unwinds (help for
     debuggers, exception handling, etc.; thanks Raphael Luba)
+  o fixed detection of native thiscall callconv for builds not using MSVC but using (or adhering to)
+    the MSVC runtime (e.g. ReactOS' MinGW based RosBE)
 dyncallback:
   o new, portable aggregate-by-value callback argument interface
   o aggregate-by-value (struct, union) support for x64 (win and sysv; thanks Raphael Luba!)

--- a/autovar/autovar_OS.h	Sat Oct 01 16:14:00 2022 +0200
+++ b/autovar/autovar_OS.h	Sun Oct 02 13:58:33 2022 +0200
@@ -49,10 +49,6 @@
 #  define OS_DragonFlyBSD
 #elif defined(__sun__) || defined(__sun) || defined(sun)
 #  define OS_SunOS
-#elif defined(__CYGWIN__)
-#  define OS_Cygwin
-#elif defined(__MINGW__)
-#  define OS_MinGW
 #elif defined(__nds__)
 #  define OS_NDS
 #elif defined(__psp__) || defined(PSP)
@@ -69,6 +65,14 @@
 #  define OS_Unknown
 #endif
 
+#if defined(DC__OS_Win32) || defined(DC__OS_Win64)
+#  if defined(__CYGWIN__)
+#    define OS_Cygwin
+#  elif defined(__MINGW32__) || defined(__MINGW64__)
+#    define OS_MinGW
+#  endif
+#endif
+
 /** Platforms. */
 
 #if defined(__ANDROID__)

--- a/dyncall/dyncall_callvm_x86.c	Sat Oct 01 16:14:00 2022 +0200
+++ b/dyncall/dyncall_callvm_x86.c	Sun Oct 02 13:58:33 2022 +0200
@@ -607,7 +607,7 @@
 
   switch(mode) {
     case DC_CALL_C_DEFAULT:
-#if !defined(DC__C_MSVC)
+#if !defined(DC__C_MSVC) && !defined(DC__RT_MSVCRT)
     case DC_CALL_C_DEFAULT_THIS:
 #endif
     case DC_CALL_C_ELLIPSIS:
@@ -619,7 +619,7 @@
     case DC_CALL_C_X86_CDECL:          vt = &gVT_x86_cdecl;          break; /* also handles DC_CALL_C_X86_WIN32_THIS_GNU */
     case DC_CALL_C_X86_WIN32_STD:      vt = &gVT_x86_win32_std;      break;
     case DC_CALL_C_X86_WIN32_FAST_MS:  vt = &gVT_x86_win32_fast_ms;  break;
-#if defined(DC__C_MSVC)
+#if defined(DC__C_MSVC) || defined(DC__RT_MSVCRT)
     case DC_CALL_C_DEFAULT_THIS:
 #endif
     case DC_CALL_C_X86_WIN32_THIS_MS:  vt = &gVT_x86_win32_this_ms;  break;

--- a/dyncall/dyncall_macros.h	Sat Oct 01 16:14:00 2022 +0200
+++ b/dyncall/dyncall_macros.h	Sun Oct 02 13:58:33 2022 +0200
@@ -50,83 +50,89 @@
 
 /* MS Windows XP x64/Vista64 or later. */
 #if defined(WIN64) || defined(_WIN64) || defined(__WIN64__)
-#define DC__OS_Win64
+# define DC__OS_Win64
 
 /* MS Windows NT/95/98/ME/2000/XP/Vista32. */
 #elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__) || defined(__WINDOWS__) || defined(_WINDOWS)
-#define DC__OS_Win32
+# define DC__OS_Win32
 
 /* All the OS' based on Darwin OS (MacOS X, OpenDarwin). Note that '__APPLE__' may be defined for classic MacOS, too. */
 /* __MACOSX__ is not defined in gcc assembler mode (switch: -S) */
-/* @@@ TODO: Check for Classic OS */
-
 #elif defined(__APPLE__) || defined(__Darwin__)
-#  define DC__OS_Darwin
-#  if defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
-#    define DC__OS_IPhone
-#  else /* defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) */
-#    define DC__OS_MacOSX
-#  endif
+# define DC__OS_Darwin
+# if defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
+#  define DC__OS_IPhone
+# else /* defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) */
+#  define DC__OS_MacOSX
+# endif
 
 /* The most popular open source Unix-like OS - Linux. */
 #elif defined(__linux__) || defined(__linux) || defined(__gnu_linux__)
-#define DC__OS_Linux
+# define DC__OS_Linux
 
 /* The most powerful open source Unix-like OS - FreeBSD. */
 #elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) /* latter is (also) used by systems using FreeBSD kernel, e.g. Debian/kFreeBSD, which could be detected specifically by also checking for __GLIBC__ */
-#define DC__OS_FreeBSD
+# define DC__OS_FreeBSD
 
 /* The most secure open source Unix-like OS - OpenBSD. */
 #elif defined(__OpenBSD__)
-#define DC__OS_OpenBSD
+# define DC__OS_OpenBSD
 
 /* The most portable open source Unix-like OS - NetBSD. */
 #elif defined(__NetBSD__)
-#define DC__OS_NetBSD
+# define DC__OS_NetBSD
 
 /* The FreeBSD fork having heavy clusterization in mind - DragonFlyBSD. */
 #elif defined(__DragonFly__)
-#define DC__OS_DragonFlyBSD
+# define DC__OS_DragonFlyBSD
 
 /* Sun's Unix-like OS - SunOS / Solaris. */
 #elif defined(__sun__) || defined(__sun) || defined(sun)
-#define DC__OS_SunOS
-
-/* The "Linux-like environment for Windows" - Cygwin. */
-#elif defined(__CYGWIN__)
-#define DC__OS_Cygwin
-
-/* The "Minimalist GNU for Windows" - MinGW. */
-#elif defined(__MINGW__)/*@@@*/
-#define DC__OS_MinGW
+# define DC__OS_SunOS
 
 /* The Nintendo DS (homebrew) using devkitpro. */
 #elif defined(__nds__)
-#define DC__OS_NDS
+# define DC__OS_NDS
 
 /* The PlayStation Portable (homebrew) SDK. */
 #elif defined(__psp__) || defined(PSP)
-#define DC__OS_PSP
+# define DC__OS_PSP
 
 /* Haiku (BeOS alike). */
 #elif defined(__HAIKU__)
-#define DC__OS_BeOS
+# define DC__OS_BeOS
 
 /* The Unix successor - Plan9 from Bell Labs */
 #elif defined(Plan9) || defined(__Plan9__)
-#define DC__OS_Plan9
+# define DC__OS_Plan9
 
 /* Digital's Unix-like OS - VMS */
 #elif defined(__vms)
-#define DC__OS_VMS
+# define DC__OS_VMS
 
+/* Tanenbaum's Microkernel OS - Minix */
 #elif defined(__minix)
-#define DC__OS_Minix
-
-#else
+# define DC__OS_Minix
 
 /* Unable to determine OS, which is probably ok (e.g. baremetal stuff, etc.). */
-#define DC__OS_UNKNOWN
+#else
+# define DC__OS_UNKNOWN
+
+#endif
+
+
+/* windows sub envs */
+#if defined(DC__OS_Win32) || defined(DC__OS_Win64)
+
+/* The "Linux-like environment for Windows" - Cygwin. */
+# if defined(__CYGWIN__)
+#  define DC__OS_Cygwin
+
+/* The "Minimalist GNU for Windows" - MinGW. */
+# elif defined(__MINGW32__) || defined(__MINGW64__)
+#  define DC__OS_MinGW
+# endif
+
 #endif
 
 
@@ -137,35 +143,35 @@
 
 /* Intel's C/C++ compiler. */
 #if defined(__INTEL_COMPILER)
-#define DC__C_Intel
+# define DC__C_Intel
 
 /* MS C/C++ compiler. */
 #elif defined(_MSC_VER)
-#define DC__C_MSVC
+# define DC__C_MSVC
 
 /* LLVM clang. */
 #elif defined(__clang__) || defined(__llvm__)
-#define DC__C_CLANG
+# define DC__C_CLANG
 
 /* The GNU Compiler Collection - GCC. */
 #elif defined(__GNUC__)
-#define DC__C_GNU
+# define DC__C_GNU
 
 /* Watcom compiler. */
 #elif defined(__WATCOMC__)
-#define DC__C_WATCOM
+# define DC__C_WATCOM
 
 /* Portable C Compiler. */
 #elif defined(__PCC__)
-#define DC__C_PCC
+# define DC__C_PCC
 
 /* Sun Pro C. */
 #elif defined(__SUNPRO_C)
-#define DC__C_SUNPRO
+# define DC__C_SUNPRO
 
 /* Undetected C Compiler. */
 #else
-#define DC__C_UNKNOWN
+# define DC__C_UNKNOWN
 #endif
 
 
@@ -181,9 +187,9 @@
 # define DC__Arch_Itanium
 #elif defined(_M_PPC) || defined(__powerpc__) || defined(__powerpc) || defined(__POWERPC__) || defined(__ppc__) || defined(__power__)
 # if defined(__ppc64__) || defined(_ARCH_PPC64) || defined(__power64__) || defined(__powerpc64__)
-#   define DC__Arch_PPC64
+#  define DC__Arch_PPC64
 # else
-#   define DC__Arch_PPC32
+#  define DC__Arch_PPC32
 # endif
 #elif defined(__mips64__) || defined(__mips64)
 # define DC__Arch_MIPS64
@@ -205,6 +211,13 @@
 
 
 
+/* -- Runtime ------------------------------------------------------- */
+
+#if defined(__MSVCRT__)
+# define DC__RT_MSVCRT
+#endif
+
+
 /* -- Rough OS classification --------------------------------------- */
 
 #if defined(DC__OS_Win32) || defined(DC__OS_Win64)
@@ -230,9 +243,9 @@
 #if defined(DC__Arch_ARM_ARM) || defined(DC__Arch_ARM_THUMB)
 # if defined(__ARM_EABI__) || defined(DC__OS_NDS)
 #  if defined (__ARM_PCS_VFP) && (__ARM_PCS_VFP == 1)
-#    define DC__ABI_ARM_HF
+#   define DC__ABI_ARM_HF
 #  else
-#    define DC__ABI_ARM_EABI
+#   define DC__ABI_ARM_EABI
 #  endif
 # elif defined(__APCS_32__)
 #  define DC__ABI_ARM_OABI
@@ -285,12 +298,12 @@
 # elif (defined(DC__Arch_PPC64) && (DC__ABI_PPC64_ELF_V == 2)) || defined(MIPSEL) || defined(_MIPSEL) || defined(__MIPSEL) || defined(__MIPSEL__) || defined(__ARMEL__) || defined(__AARCH64EL__)
 #  define DC__Endian_LITTLE
 # elif defined(DC__Arch_Sparc64) && !defined(__BYTE_ORDER__) /* Sparc64 default is big-endian, except if explicitly defined */
-#    define DC__Endian_BIG
+#   define DC__Endian_BIG
 # elif defined(BYTE_ORDER) || defined(_BYTE_ORDER) || defined(__BYTE_ORDER__) /* explicitly set byte order, either through compiler or platform specific endian.h */
 #  if (defined(BIG_ENDIAN) && (BYTE_ORDER == BIG_ENDIAN)) ||  (defined(_BIG_ENDIAN) && (_BYTE_ORDER == _BIG_ENDIAN)) || (defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
-#    define DC__Endian_BIG
+#   define DC__Endian_BIG
 #  elif (defined(LITTLE_ENDIAN) && (BYTE_ORDER == LITTLE_ENDIAN)) ||  (defined(_LITTLE_ENDIAN) && (_BYTE_ORDER == _LITTLE_ENDIAN)) || (defined(__ORDER_LITTLE_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
-#    define DC__Endian_LITTLE
+#   define DC__Endian_LITTLE
 #  endif
 # elif (defined(_BIG_ENDIAN) && (_BIG_ENDIAN == 1)) || (defined(__BIG_ENDIAN__) && (__BIG_ENDIAN__ == 1)) /* explicitly set as on/off */
 #  define DC__Endian_BIG
@@ -317,12 +330,12 @@
 /* syscalls */
 #if (defined(DC__Arch_Intel_x86) || (defined(DC__Arch_AMD64) && defined(DC_UNIX)) || defined(DC__Arch_PPC32) || defined(DC__Arch_PPC64)) && \
     !defined(DC__OS_MacOSX) && !defined(DC__OS_Plan9) && !defined(DC__OS_NDS) && !defined(DC__OS_PSP) && !defined(DC__OS_Minix) && !defined(DC__OS_SunOS) && !defined(DC__OS_BeOS)
-#  define DC__Feature_Syscall
+# define DC__Feature_Syscall
 #endif
 
 /* aggregate (struct, union) by value */
 #if defined(DC__Arch_AMD64)
-#  define DC__Feature_AggrByVal
+# define DC__Feature_AggrByVal
 #endif