[Bug 3511806] Compiler checks too early

(autoconf still to be run!)

7 files changed, 225 insertions, 252 deletions

diff --git a/ChangeLog b/ChangeLog
index bffb230..b13ebb5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2012-03-30  Jan Nijtmans  <nijtmans@users.sf.net>
+
+	* unix/tcl.m4:               [Bug 3511806] Compiler checks too early
+	* unix/configure.in:         This change allows to build the cygwin
+	* unix/tclUnixPort.h:        and mingw32 ports of Tcl/Tk to build
+	* win/tcl.m4:                out-of-the-box using a native or cross-
+	* win/configure.in:          compiler.
+	* win/tclWinPort.h:          (autoconf still to be run!)
+
 2012-03-27  Jan Nijtmans  <nijtmans@users.sf.net>
 
 	* generic/tcl.h:             [Bug 3508771] Wrong Tcl_StatBuf used on MinGW
diff --git a/unix/configure.in b/unix/configure.in
index a30c2b4..b3df242 100644
--- a/unix/configure.in
+++ b/unix/configure.in
@@ -247,7 +247,9 @@ SC_TIME_HANDLER
 #	lack blkcnt_t.
 #--------------------------------------------------------------------
 
+if test "$ac_cv_cygwin" != "yes"; then
 AC_CHECK_MEMBERS([struct stat.st_blocks, struct stat.st_blksize])
+fi
 AC_CHECK_TYPES([blkcnt_t])
 AC_CHECK_FUNC(fstatfs, , [AC_DEFINE(NO_FSTATFS, 1, [Do we have fstatfs()?])])
 
@@ -381,7 +383,7 @@ AC_CHECK_FUNC(opendir, , [AC_DEFINE(USE_DIRENT2_H, 1, [May we include <dirent2.h
 #--------------------------------------------------------------------
 
 AC_CACHE_CHECK([union wait], tcl_cv_union_wait, [
-    AC_TRY_LINK([#include <sys/types.h> 
+    AC_TRY_LINK([#include <sys/types.h>
 #include <sys/wait.h>], [
 union wait x;
 WIFEXITED(x);		/* Generates compiler error if WIFEXITED
@@ -590,7 +592,7 @@ fi
 
 #--------------------------------------------------------------------
 #	The statements below check for systems where POSIX-style
-#	non-blocking I/O (O_NONBLOCK) doesn't work or is unimplemented. 
+#	non-blocking I/O (O_NONBLOCK) doesn't work or is unimplemented.
 #	On these systems (mostly older ones), use the old BSD-style
 #	FIONBIO approach instead.
 #--------------------------------------------------------------------
@@ -785,12 +787,12 @@ if test "$FRAMEWORK_BUILD" = "1" ; then
     PRIVATE_INCLUDE_DIR="${libdir}/PrivateHeaders"
     HTML_DIR="${libdir}/Resources/Documentation/Reference/Tcl"
     EXTRA_INSTALL="install-private-headers html-tcl"
-    EXTRA_BUILD_HTML='@ln -fs contents.htm "$(HTML_INSTALL_DIR)"/TclTOC.html' 
+    EXTRA_BUILD_HTML='@ln -fs contents.htm "$(HTML_INSTALL_DIR)"/TclTOC.html'
     EXTRA_INSTALL_BINARIES='@echo "Installing Info.plist to $(LIB_INSTALL_DIR)/Resources" && mkdir -p "$(LIB_INSTALL_DIR)/Resources" && $(INSTALL_DATA) Tcl-Info.plist "$(LIB_INSTALL_DIR)/Resources/Info.plist"'
     EXTRA_INSTALL_BINARIES="$EXTRA_INSTALL_BINARIES"' && echo "Installing license.terms to $(LIB_INSTALL_DIR)/Resources" && $(INSTALL_DATA) "$(TOP_DIR)/license.terms" "$(LIB_INSTALL_DIR)/Resources"'
     EXTRA_INSTALL_BINARIES="$EXTRA_INSTALL_BINARIES"' && echo "Finalizing Tcl.framework" && rm -f "$(LIB_INSTALL_DIR)/../Current" && ln -s "$(VERSION)" "$(LIB_INSTALL_DIR)/../Current" && for f in "$(LIB_FILE)" tclConfig.sh Resources Headers PrivateHeaders; do rm -f "$(LIB_INSTALL_DIR)/../../$$f" && ln -s "Versions/Current/$$f" "$(LIB_INSTALL_DIR)/../.."; done && f="$(STUB_LIB_FILE)" && rm -f "$(LIB_INSTALL_DIR)/../../$$f" && ln -s "Versions/$(VERSION)/$$f" "$(LIB_INSTALL_DIR)/../.."'
-    # Don't use AC_DEFINE for the following as the framework version define 
-    # needs to go into the Makefile even when using autoheader, so that we  
+    # Don't use AC_DEFINE for the following as the framework version define
+    # needs to go into the Makefile even when using autoheader, so that we
     # can pick up a potential make override of VERSION. Also, don't put this
     # into CFLAGS as it should not go into tclConfig.sh
     EXTRA_CC_SWITCHES='-DTCL_FRAMEWORK_VERSION=\"$(VERSION)\"'
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index fe9b136..ca77586 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -1237,7 +1237,7 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	    CC_SEARCH_FLAGS=""
 	    LD_SEARCH_FLAGS=""
 	    ;;
-	CYGWIN_*)
+	CYGWIN_*|MINGW32*)
 	    SHLIB_CFLAGS=""
 	    SHLIB_LD='${CC} -shared'
 	    SHLIB_SUFFIX=".dll"
@@ -1248,6 +1248,19 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	    TCL_NEEDS_EXP_FILE=1
 	    TCL_EXPORT_FILE_SUFFIX='${VERSION}\$\{DBGX\}.dll.a'
 	    TCL_SHLIB_LD_EXTRAS='-Wl,--out-implib,$[@].a'
+	    AC_CACHE_CHECK(for Cygwin version of gcc,
+		ac_cv_cygwin,
+		AC_TRY_COMPILE([
+		#ifdef __CYGWIN__
+		    #error cygwin
+		#endif
+		], [],
+		ac_cv_cygwin=no,
+		ac_cv_cygwin=yes)
+	    )
+	    if test "$ac_cv_cygwin" = "no"; then
+		AC_MSG_ERROR([${CC} is not a cygwin compiler.])
+	    fi
 	    ;;
 	dgux*)
 	    SHLIB_CFLAGS="-K PIC"
@@ -2069,7 +2082,7 @@ dnl # preprocessing tests use only CPPFLAGS.
 	case $system in
 	    AIX-*) ;;
 	    BSD/OS*) ;;
-	    CYGWIN_*) ;;
+	    CYGWIN_*|MINGW32_*) ;;
 	    IRIX*) ;;
 	    NetBSD-*|FreeBSD-*|OpenBSD-*) ;;
 	    Darwin-*) ;;
@@ -2114,6 +2127,25 @@ dnl # preprocessing tests use only CPPFLAGS.
         TCL_LIBS="${DL_LIBS} ${LIBS} ${MATH_LIBS}"])
     AC_SUBST(TCL_LIBS)
 
+	# See if the compiler supports casting to a union type.
+	# This is used to stop gcc from printing a compiler
+	# warning when initializing a union member.
+
+	AC_CACHE_CHECK(for cast to union support,
+	    tcl_cv_cast_to_union,
+	    AC_TRY_COMPILE([],
+	    [
+		  union foo { int i; double d; };
+		  union foo f = (union foo) (int) 0;
+	    ],
+	    tcl_cv_cast_to_union=yes,
+	    tcl_cv_cast_to_union=no)
+	)
+	if test "$tcl_cv_cast_to_union" = "yes"; then
+	    AC_DEFINE(HAVE_CAST_TO_UNION, 1,
+		    [Defined when compiler supports casting to union type.])
+	fi
+
     # FIXME: This subst was left in only because the TCL_DL_LIBS
     # entry in tclConfig.sh uses it. It is not clear why someone
     # would use TCL_DL_LIBS instead of TCL_LIBS.
diff --git a/unix/tclUnixPort.h b/unix/tclUnixPort.h
index fef748b..82fc8bb 100644
--- a/unix/tclUnixPort.h
+++ b/unix/tclUnixPort.h
@@ -76,8 +76,6 @@ typedef off_t		Tcl_SeekOffset;
 #ifdef __CYGWIN__
 MODULE_SCOPE int TclOSstat(const char *name, Tcl_StatBuf *statBuf);
 MODULE_SCOPE int TclOSlstat(const char *name, Tcl_StatBuf *statBuf);
-#undef HAVE_STRUCT_STAT_ST_BLOCKS
-#undef HAVE_STRUCT_STAT_ST_BLKSIZE
 #elif defined(HAVE_STRUCT_STAT64)
 #   define TclOSstat		stat64
 #   define TclOSlstat		lstat64
diff --git a/win/configure.in b/win/configure.in
index 1b8c25a..dd1f745 100644
--- a/win/configure.in
+++ b/win/configure.in
@@ -67,225 +67,6 @@ AC_CHECK_TOOL(RC, windres)
 AC_PROG_MAKE_SET
 
 #--------------------------------------------------------------------
-# Perform additinal compiler tests.
-#--------------------------------------------------------------------
-
-dnl Currently AC_CYGWIN is disabled since it invokes AC_CANONICAL_HOST
-dnl under autoconf 2.5X.
-dnl
-dnl AC_CYGWIN
-
-AC_CACHE_CHECK(for Cygwin version of gcc,
-    ac_cv_cygwin,
-AC_TRY_COMPILE([
-#ifdef __CYGWIN__
-#error cygwin
-#endif
-],
-[],
-        ac_cv_cygwin=no,
-        ac_cv_cygwin=yes)
-)
-if test "$ac_cv_cygwin" = "yes" ; then
-    AC_MSG_ERROR([Compiling under Cygwin is not currently supported.
-A maintainer for the Cygwin port of Tcl/Tk is needed. See the README
-file for information about building with Mingw.])
-fi
-
-
-AC_CACHE_CHECK(for SEH support in compiler,
-    tcl_cv_seh,
-AC_TRY_RUN([
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-
-int main(int argc, char** argv) {
-    int a, b = 0;
-    __try {
-        a = 666 / b;
-    }
-    __except (EXCEPTION_EXECUTE_HANDLER) {
-        return 0;
-    }
-    return 1;
-}
-],
-        tcl_cv_seh=yes,
-        tcl_cv_seh=no,
-        tcl_cv_seh=no)
-)
-if test "$tcl_cv_seh" = "no" ; then
-    AC_DEFINE(HAVE_NO_SEH, 1,
-            [Defined when mingw does not support SEH])
-fi
-
-#
-# Check to see if the excpt.h include file provided contains the
-# definition for EXCEPTION_DISPOSITION; if not, which is the case
-# with Cygwin's version as of 2002-04-10, define it to be int,
-# sufficient for getting the current code to work.
-#
-AC_CACHE_CHECK(for EXCEPTION_DISPOSITION support in include files,
-    tcl_cv_eh_disposition,
-AC_TRY_COMPILE([
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-],
-[
-  EXCEPTION_DISPOSITION x;
-],
-        tcl_cv_eh_disposition=yes,
-        tcl_cv_eh_disposition=no)
-)
-if test "$tcl_cv_eh_disposition" = "no" ; then
-    AC_DEFINE(EXCEPTION_DISPOSITION, int,
-            [Defined when cygwin/mingw does not support EXCEPTION DISPOSITION])
-fi
-
-
-# Check to see if the winsock2.h include file provided contains
-# typedefs like LPFN_ACCEPT and friends.
-#
-AC_CACHE_CHECK(for LPFN_ACCEPT support in winsock2.h,
-    tcl_cv_lpfn_decls,
-AC_TRY_COMPILE([
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-#include <winsock2.h>
-],
-[
-  LPFN_ACCEPT accept;
-],
-        tcl_cv_lpfn_decls=yes,
-        tcl_cv_lpfn_decls=no)
-)
-if test "$tcl_cv_lpfn_decls" = "no" ; then
-    AC_DEFINE(HAVE_NO_LPFN_DECLS, 1,
-            [Defined when cygwin/mingw does not support LPFN_ACCEPT and friends.])
-fi
-
-# Check to see if winnt.h defines CHAR, SHORT, and LONG
-# even if VOID has already been #defined. The win32api
-# used by mingw and cygwin is known to do this.
-
-AC_CACHE_CHECK(for winnt.h that ignores VOID define,
-    tcl_cv_winnt_ignore_void,
-AC_TRY_COMPILE([
-#define VOID void
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-],
-[
-  CHAR c;
-  SHORT s;
-  LONG l;
-],
-        tcl_cv_winnt_ignore_void=yes,
-        tcl_cv_winnt_ignore_void=no)
-)
-if test "$tcl_cv_winnt_ignore_void" = "yes" ; then
-    AC_DEFINE(HAVE_WINNT_IGNORE_VOID, 1,
-            [Defined when cygwin/mingw ignores VOID define in winnt.h])
-fi
-
-# Check to see if malloc.h is missing the alloca function
-# declaration. This is known to be a problem with Mingw.
-# If we compiled without the function declaration, it
-# would work but we would get a warning message from gcc.
-# If we add the function declaration ourselves, it
-# would not compile correctly because the _alloca
-# function expects the argument to be passed in a
-# register and not on the stack. Instead, we just
-# call it from inline asm code.
-
-AC_CACHE_CHECK(for alloca declaration in malloc.h,
-    tcl_cv_malloc_decl_alloca,
-AC_TRY_COMPILE([
-#include <malloc.h>
-],
-[
-  size_t arg = 0;
-  void* ptr;
-  ptr = alloca;
-  ptr = alloca(arg);
-],
-        tcl_cv_malloc_decl_alloca=yes,
-        tcl_cv_malloc_decl_alloca=no)
-)
-if test "$tcl_cv_malloc_decl_alloca" = "no" &&
-   test "${GCC}" = "yes" ; then
-    AC_DEFINE(HAVE_ALLOCA_GCC_INLINE, 1,
-            [Defined when gcc should use inline ASM to call alloca.])
-fi
-
-# See if the compiler supports casting to a union type.
-# This is used to stop gcc from printing a compiler
-# warning when initializing a union member.
-
-AC_CACHE_CHECK(for cast to union support,
-    tcl_cv_cast_to_union,
-AC_TRY_COMPILE([],
-[
-  union foo { int i; double d; };
-  union foo f = (union foo) (int) 0;
-],
-        tcl_cv_cast_to_union=yes,
-        tcl_cv_cast_to_union=no)
-)
-if test "$tcl_cv_cast_to_union" = "yes"; then
-    AC_DEFINE(HAVE_CAST_TO_UNION, 1,
-            [Defined when compiler supports casting to union type.])
-fi
-
-# See if declarations like FINDEX_INFO_LEVELS are
-# missing from winbase.h. This is known to be
-# a problem with VC++ 5.2.
-
-AC_CACHE_CHECK(for FINDEX_INFO_LEVELS in winbase.h,
-    tcl_cv_findex_enums,
-AC_TRY_COMPILE([
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-],
-[
-  FINDEX_INFO_LEVELS i;
-  FINDEX_SEARCH_OPS j;
-],
-        tcl_cv_findex_enums=yes,
-        tcl_cv_findex_enums=no)
-)
-if test "$tcl_cv_findex_enums" = "no"; then
-    AC_DEFINE(HAVE_NO_FINDEX_ENUMS, 1,
-            [Defined when enums are missing from winbase.h])
-fi
-
-# See if MWMO_ALERTABLE is missing from winuser.h
-# This is known to be a problem with Mingw.
-
-AC_CACHE_CHECK(for MWMO_ALERTABLE in winuser.h,
-    tcl_cv_mwmo_alertable,
-AC_TRY_COMPILE([
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-],
-[
-  int i = MWMO_ALERTABLE;
-],
-        tcl_cv_mwmo_alertable=yes,
-        tcl_cv_mwmo_alertable=no)
-)
-if test "$tcl_cv_mwmo_alertable" = "no"; then
-    AC_DEFINE(HAVE_NO_MWMO_ALERTABLE, 1,
-            [Defined when MWMO_ALERTABLE is missing from winuser.h])
-fi
-
-#--------------------------------------------------------------------
 # Determines the correct binary file extension (.o, .obj, .exe etc.)
 #--------------------------------------------------------------------
 
@@ -351,6 +132,33 @@ AC_CHECK_TYPE([uintptr_t], [
     fi
 ])
 #--------------------------------------------------------------------
+# Perform additinal compiler tests.
+#--------------------------------------------------------------------
+
+# See if declarations like FINDEX_INFO_LEVELS are
+# missing from winbase.h. This is known to be
+# a problem with VC++ 5.2.
+
+AC_CACHE_CHECK(for FINDEX_INFO_LEVELS in winbase.h,
+    tcl_cv_findex_enums,
+AC_TRY_COMPILE([
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#undef WIN32_LEAN_AND_MEAN
+],
+[
+  FINDEX_INFO_LEVELS i;
+  FINDEX_SEARCH_OPS j;
+],
+        tcl_cv_findex_enums=yes,
+        tcl_cv_findex_enums=no)
+)
+if test "$tcl_cv_findex_enums" = "no"; then
+    AC_DEFINE(HAVE_NO_FINDEX_ENUMS, 1,
+            [Defined when enums are missing from winbase.h])
+fi
+
+#--------------------------------------------------------------------
 # Set the default compiler switches based on the --enable-symbols
 # option.  This macro depends on C flags, and should be called
 # after SC_CONFIG_CFLAGS macro is called.
diff --git a/win/tcl.m4 b/win/tcl.m4
index 83a4ea3..9a5fa7b 100644
--- a/win/tcl.m4
+++ b/win/tcl.m4
@@ -411,6 +411,39 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
     # which requires x86|amd64|ia64.
     MACHINE="X86"
 
+    if test "$GCC" = "yes"; then
+
+      AC_CACHE_CHECK(for cross-compile version of gcc,
+	ac_cv_cross,
+	AC_TRY_COMPILE([
+	    #ifdef __WIN32__
+		#error cross-compiler
+	    #endif
+	], [],
+	ac_cv_cross=yes,
+	ac_cv_cross=no)
+      )
+
+      if test "$ac_cv_cross" = "yes"; then
+	case "$do64bit" in
+	    amd64|x64|yes)
+		CC="x86_64-w64-mingw32-gcc"
+		LD="x86_64-w64-mingw32-ld"
+		AR="x86_64-w64-mingw32-ar"
+		RANLIB="x86_64-w64-mingw32-ranlib"
+		RC="x86_64-w64-mingw32-windres"
+	    ;;
+	    *)
+		CC="i686-w64-mingw32-gcc"
+		LD="i686-w64-mingw32-ld"
+		AR="i686-w64-mingw32-ar"
+		RANLIB="i686-w64-mingw32-ranlib"
+		RC="i686-w64-mingw32-windres"
+	    ;;
+	esac
+      fi
+    fi
+
     # Check for a bug in gcc's windres that causes the
     # compile to fail when a Windows native path is
     # passed into windres. The mingw toolchain requires
@@ -436,7 +469,7 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	cyg_conftest=
     fi
 
-    if test "$CYGPATH" = "echo" || test "$ac_cv_cygwin" = "yes"; then
+    if test "$CYGPATH" = "echo"; then
         DEPARG='"$<"'
     else
         DEPARG='"$(shell $(CYGPATH) $<)"'
@@ -444,6 +477,22 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 
     # set various compiler flags depending on whether we are using gcc or cl
 
+    if test "${GCC}" = "yes" ; then
+	AC_CACHE_CHECK(for mingw32 version of gcc,
+	    ac_cv_win32,
+	    AC_TRY_COMPILE([
+		#ifdef __WIN32__
+		    #error win32
+		#endif
+	    ], [],
+	    ac_cv_win32=no,
+	    ac_cv_win32=yes)
+	)
+	if test "$ac_cv_win32" != "yes"; then
+	    AC_MSG_ERROR([${CC} cannot produce win32 executables.])
+	fi
+    fi
+
     AC_MSG_CHECKING([compiler flags])
     if test "${GCC}" = "yes" ; then
 	SHLIB_LD=""
@@ -465,21 +514,6 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	extra_cflags="-pipe"
 	extra_ldflags="-pipe"
 
-	if test "$ac_cv_cygwin" = "yes"; then
-	  touch ac$$.c
-	  if ${CC} -c -mwin32 ac$$.c >/dev/null 2>&1; then
-	    case "$extra_cflags" in
-	      *-mwin32*) ;;
-	      *) extra_cflags="-mwin32 $extra_cflags" ;;
-	    esac
-	    case "$extra_ldflags" in
-	      *-mwin32*) ;;
-	      *) extra_ldflags="-mwin32 $extra_ldflags" ;;
-	    esac
-	  fi
-	  rm -f ac$$.o ac$$.c
-	fi
-
 	if test "${SHARED_BUILD}" = "0" ; then
 	    # static
             AC_MSG_RESULT([using static flags])
@@ -559,9 +593,9 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 		;;
 	    *)
 		AC_TRY_COMPILE([
-			#ifdef _WIN64
+		    #ifdef _WIN64
 			#error 64-bit
-			#endif
+		    #endif
 		], [],
 			tcl_win_64bit=no,
 			tcl_win_64bit=yes
@@ -792,6 +826,101 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 	AC_DEFINE(TCL_CFG_DO64BIT)
     fi
 
+    if test "${GCC}" = "yes" ; then
+	AC_CACHE_CHECK(for SEH support in compiler,
+	    tcl_cv_seh,
+	AC_TRY_RUN([
+	    #define WIN32_LEAN_AND_MEAN
+	    #include <windows.h>
+	    #undef WIN32_LEAN_AND_MEAN
+
+	    int main(int argc, char** argv) {
+		int a, b = 0;
+		__try {
+		    a = 666 / b;
+		}
+		__except (EXCEPTION_EXECUTE_HANDLER) {
+		    return 0;
+		}
+		return 1;
+	    }
+	],
+	    tcl_cv_seh=yes,
+	    tcl_cv_seh=no,
+	    tcl_cv_seh=no)
+	)
+	if test "$tcl_cv_seh" = "no" ; then
+	    AC_DEFINE(HAVE_NO_SEH, 1,
+		    [Defined when mingw does not support SEH])
+	fi
+
+	#
+	# Check to see if the excpt.h include file provided contains the
+	# definition for EXCEPTION_DISPOSITION; if not, which is the case
+	# with Cygwin's version as of 2002-04-10, define it to be int,
+	# sufficient for getting the current code to work.
+	#
+	AC_CACHE_CHECK(for EXCEPTION_DISPOSITION support in include files,
+	    tcl_cv_eh_disposition,
+	    AC_TRY_COMPILE([
+#	    define WIN32_LEAN_AND_MEAN
+#	    include <windows.h>
+#	    undef WIN32_LEAN_AND_MEAN
+	    ],[
+		EXCEPTION_DISPOSITION x;
+	    ],
+		tcl_cv_eh_disposition=yes,
+		tcl_cv_eh_disposition=no)
+	)
+	if test "$tcl_cv_eh_disposition" = "no" ; then
+	AC_DEFINE(EXCEPTION_DISPOSITION, int,
+		[Defined when cygwin/mingw does not support EXCEPTION DISPOSITION])
+	fi
+
+	# Check to see if winnt.h defines CHAR, SHORT, and LONG
+	# even if VOID has already been #defined. The win32api
+	# used by mingw and cygwin is known to do this.
+
+	AC_CACHE_CHECK(for winnt.h that ignores VOID define,
+	    tcl_cv_winnt_ignore_void,
+	    AC_TRY_COMPILE([
+		#define VOID void
+		#define WIN32_LEAN_AND_MEAN
+		#include <windows.h>
+		#undef WIN32_LEAN_AND_MEAN
+	    ], [
+		CHAR c;
+		SHORT s;
+		LONG l;
+	    ],
+        tcl_cv_winnt_ignore_void=yes,
+        tcl_cv_winnt_ignore_void=no)
+	)
+	if test "$tcl_cv_winnt_ignore_void" = "yes" ; then
+	    AC_DEFINE(HAVE_WINNT_IGNORE_VOID, 1,
+		    [Defined when cygwin/mingw ignores VOID define in winnt.h])
+	fi
+
+	# See if the compiler supports casting to a union type.
+	# This is used to stop gcc from printing a compiler
+	# warning when initializing a union member.
+
+	AC_CACHE_CHECK(for cast to union support,
+	    tcl_cv_cast_to_union,
+	    AC_TRY_COMPILE([],
+	    [
+		  union foo { int i; double d; };
+		  union foo f = (union foo) (int) 0;
+	    ],
+	    tcl_cv_cast_to_union=yes,
+	    tcl_cv_cast_to_union=no)
+	)
+	if test "$tcl_cv_cast_to_union" = "yes"; then
+	    AC_DEFINE(HAVE_CAST_TO_UNION, 1,
+		    [Defined when compiler supports casting to union type.])
+	fi
+    fi
+
     # DL_LIBS is empty, but then we match the Unix version
     AC_SUBST(DL_LIBS)
     AC_SUBST(CFLAGS_DEBUG)
diff --git a/win/tclWinPort.h b/win/tclWinPort.h
index e2cac52..da685ad 100644
--- a/win/tclWinPort.h
+++ b/win/tclWinPort.h
@@ -371,11 +371,6 @@ typedef DWORD_PTR * PDWORD_PTR;
 #endif /* __BORLANDC__ */
 
 #ifdef __WATCOMC__
-    /*
-     * OpenWatcom uses a wine derived winsock2.h that is missing the
-     * LPFN_* typedefs.
-     */
-#   define HAVE_NO_LPFN_DECLS
 #   if !defined(__CHAR_SIGNED__)
 #	error "You must use the -j switch to ensure char is signed."
 #   endif
@@ -438,7 +433,7 @@ typedef DWORD_PTR * PDWORD_PTR;
 /*
  * Older version of Mingw are known to lack a MWMO_ALERTABLE define.
  */
-#if defined(HAVE_NO_MWMO_ALERTABLE)
+#if !defined(MWMO_ALERTABLE)
 #   define MWMO_ALERTABLE 2
 #endif