Fix building and using the library with MinGW -std=c++{98,11} options.

These options enable "strict ANSI" mode in MinGW which omits declarations of
POSIX functions from the standard headers. To allow the library and, possibly
even more importantly, the user code including our headers, to compile with
these options, declare the functions that we need ourselves.

This might appear to go against the spirit of "strict ANSI" mode, but the only
alternative would be to not use such functions at all and silently cripple the
library when -std=c++NN is used, compared to -std=g++NN case, and this doesn't
seem appealing neither.

Closes #16984.

include/wx/filefn.h

@@ -216,8 +216,22 @@ enum wxPosixPermissions
         #define wxFtell _ftelli64
     #elif wxCHECK_MINGW32_VERSION(3, 5) // mingw-runtime version (not gcc)
         #define wxHAS_HUGE_STDIO_FILES
+
+        wxDECL_FOR_STRICT_MINGW32(int, fseeko64, (FILE*, long long, int));
         #define wxFseek fseeko64
-        #define wxFtell ftello64
+
+        #ifdef wxNEEDS_STRICT_ANSI_WORKAROUNDS
+            // Unfortunately ftello64() is not defined in the library for
+            // whatever reason but as an inline function, so define wxFtell()
+            // here similarly.
+            inline long long wxFtell(FILE* fp)
+            {
+                fpos_t pos;
+                return fgetpos(fp, &pos) == 0 ? pos : -1LL;
+            }
+        #else
+            #define wxFtell ftello64
+        #endif
     #endif
 
     // other Windows compilers (DMC, Watcom, and Borland) don't have huge file
@@ -376,7 +390,7 @@ enum wxPosixPermissions
 
     // finally the default char-type versions
     #if wxUSE_UNICODE
-        #if wxUSE_UNICODE_MSLU || defined(__WX_STRICT_ANSI_GCC__)
+        #if wxUSE_UNICODE_MSLU
             // implement the missing file functions in Win9x ourselves
             WXDLLIMPEXP_BASE int wxMSLU__wopen(const wxChar *name,
                                                int flags, int mode);
@@ -404,6 +418,9 @@ enum wxPosixPermissions
             #define wxCRT_MkDir     wxCRT_MkDirW
             #define wxCRT_RmDir     wxCRT_RmDirW
             #define wxCRT_Stat      wxCRT_StatW
+
+            wxDECL_FOR_STRICT_MINGW32(int, _wmkdir, (const wchar_t*))
+            wxDECL_FOR_STRICT_MINGW32(int, _wrmdir, (const wchar_t*))
         #endif // wxUSE_UNICODE_MSLU/!wxUSE_UNICODE_MSLU
     #else // !wxUSE_UNICODE
         #define wxCRT_Open      wxCRT_OpenA

include/wx/math.h

@@ -71,6 +71,10 @@
     #else
         #define wxFinite(x) isfinite(x)
     #endif
+#elif defined(wxNEEDS_STRICT_ANSI_WORKAROUNDS)
+    wxDECL_FOR_STRICT_MINGW32(int, _finite, (double));
+
+    #define wxFinite(x) _finite(x)
 #elif ( defined(__GNUG__)||defined(__GNUWIN32__)||defined(__DJGPP__)|| \
       defined(__SGI_CC__)||defined(__SUNCC__)||defined(__XLC__)|| \
       defined(__HPUX__) ) && ( !defined(wxOSX_USE_IPHONE) || wxOSX_USE_IPHONE == 0 )

include/wx/msw/gccpriv.h

@@ -156,5 +156,28 @@
     #endif
 #endif
 
+/*
+    Traditional MinGW (but not MinGW-w64 nor TDM-GCC) omits many POSIX
+    functions from their headers when compiled with __STRICT_ANSI__ defined.
+    Unfortunately this means that they are not available when using -std=c++98
+    (not very common) or -std=c++11 (much more so), but we still need them even
+    in this case. As the intention behind using -std=c++11 is probably to get
+    the new C++11 features and not disable the use of POSIX functions, we just
+    manually declare the functions we need in this case if necessary.
+ */
+#if defined(__MINGW32_TOOLCHAIN__) && defined(__STRICT_ANSI__)
+    #define wxNEEDS_STRICT_ANSI_WORKAROUNDS
+
+    /*
+        This macro is somewhat unusual as it takes the list of parameters
+        inside parentheses and includes semicolon inside it as putting the
+        semicolon outside wouldn't do the right thing when this macro is empty.
+     */
+    #define wxDECL_FOR_STRICT_MINGW32(rettype, func, params) \
+        extern "C" _CRTIMP rettype __cdecl __MINGW_NOTHROW func params ;
+#else
+    #define wxDECL_FOR_STRICT_MINGW32(rettype, func, params)
+#endif
+
 #endif
   /* _WX_MSW_GCCPRIV_H_ */

include/wx/msw/private.h

@@ -183,6 +183,8 @@ extern LONG APIENTRY _EXPORT
    || defined(__MINGW32__)
     #define wxGetOSFHandle(fd) ((HANDLE)_get_osfhandle(fd))
     #define wxOpenOSFHandle(h, flags) (_open_osfhandle(wxPtrToUInt(h), flags))
+
+    wxDECL_FOR_STRICT_MINGW32(FILE*, _fdopen, (int, const char*))
     #define wx_fdopen _fdopen
 #endif
 

include/wx/wxcrtbase.h

@@ -73,6 +73,9 @@
 
 #ifdef wxNEED_ISASCII
     inline int isascii(int c) { return (unsigned)c < 0x80; }
+
+    // Avoid further (re)definitions of it.
+    #define isascii isascii
 #endif
 
 #ifdef _WIN32_WCE
@@ -445,7 +448,7 @@ WXDLLIMPEXP_BASE wchar_t *wxCRT_StrtokW(wchar_t *psz, const wchar_t *delim, wcha
 #else /* Unicode filenames */
     /* special case: these functions are missing under Win9x with Unicows so we
        have to implement them ourselves */
-    #if wxUSE_UNICODE_MSLU || defined(__WX_STRICT_ANSI_GCC__)
+    #if wxUSE_UNICODE_MSLU
             WXDLLIMPEXP_BASE FILE* wxMSLU__wfopen(const wchar_t *name, const wchar_t *mode);
             WXDLLIMPEXP_BASE FILE* wxMSLU__wfreopen(const wchar_t *name, const wchar_t *mode, FILE *stream);
             WXDLLIMPEXP_BASE int wxMSLU__wrename(const wchar_t *oldname, const wchar_t *newname);
@@ -455,6 +458,11 @@ WXDLLIMPEXP_BASE wchar_t *wxCRT_StrtokW(wchar_t *psz, const wchar_t *delim, wcha
             #define wxCRT_Remove    wxMSLU__wremove
             #define wxCRT_Rename    wxMSLU__wrename
     #else
+        wxDECL_FOR_STRICT_MINGW32(FILE*, _wfopen, (const wchar_t*, const wchar_t*))
+        wxDECL_FOR_STRICT_MINGW32(FILE*, _wfreopen, (const wchar_t*, const wchar_t*, FILE*))
+        wxDECL_FOR_STRICT_MINGW32(int, _wrename, (const wchar_t*, const wchar_t*))
+        wxDECL_FOR_STRICT_MINGW32(int, _wremove, (const wchar_t*))
+
         /* WinCE CRT doesn't provide these functions so use our own */
         #ifdef __WXWINCE__
             WXDLLIMPEXP_BASE int wxCRT_Rename(const wchar_t *src,

src/common/filefn.cpp

@@ -90,6 +90,8 @@
     #define HAVE_WGETCWD
 #endif
 
+wxDECL_FOR_STRICT_MINGW32(int, _fileno, (FILE*))
+
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------

src/common/time.cpp

@@ -22,6 +22,23 @@
     #pragma hdrstop
 #endif
 
+// This is a horrible hack which only works because we don't currently include
+// <time.h> from wx/wxprec.h. It is needed because we need timezone-related
+// stuff from MinGW time.h, but it is not compiled in strict ANSI mode and it
+// is too complicated to be dealt with using wxDECL_FOR_STRICT_MINGW32(). So we
+// just include the header after undefining __STRICT_ANSI__ to get all the
+// declarations we need -- and then define it back to avoid inconsistencies in
+// all our other headers.
+//
+// Note that the same hack is used for "environ" in utilscmn.cpp, so if the
+// code here is modified because this hack becomes unnecessary or a better
+// solution is found, the code there should be updated as well.
+#ifdef wxNEEDS_STRICT_ANSI_WORKAROUNDS
+    #undef __STRICT_ANSI__
+    #include <time.h>
+    #define __STRICT_ANSI__
+#endif
+
 #include "wx/time.h"
 
 #ifndef WX_PRECOMP

src/common/utilscmn.cpp

@@ -23,6 +23,14 @@
     #pragma hdrstop
 #endif
 
+// See comment about this hack in time.cpp: here we do it for environ external
+// variable which can't be easily declared when using MinGW in strict ANSI mode.
+#ifdef wxNEEDS_STRICT_ANSI_WORKAROUNDS
+    #undef __STRICT_ANSI__
+    #include <stdlib.h>
+    #define __STRICT_ANSI__
+#endif
+
 #ifndef WX_PRECOMP
     #include "wx/app.h"
     #include "wx/string.h"

src/common/wxcrt.cpp

@@ -73,6 +73,10 @@
     #include <xlocale.h>
 #endif
 
+wxDECL_FOR_STRICT_MINGW32(int, vswprintf, (wchar_t*, const wchar_t*, __VALIST));
+wxDECL_FOR_STRICT_MINGW32(int, _putws, (const wchar_t*));
+wxDECL_FOR_STRICT_MINGW32(void, _wperror, (const wchar_t*));
+
 WXDLLIMPEXP_BASE size_t wxMB2WC(wchar_t *buf, const char *psz, size_t n)
 {
   // assume that we have mbsrtowcs() too if we have wcsrtombs()

src/stc/scintilla/include/Scintilla.h

@@ -42,6 +42,17 @@ typedef long sptr_t;
 
 typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam, sptr_t lParam);
 
+/* Workaround for building with MinGW (not MinGW-w64) in strict ANSI mode which
+ * is, notably, enabled by -std=c++NN options. */
+#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR) && defined(__STRICT_ANSI__)
+/* Other headers included by an application using Scintilla might already
+ * define isascii() too, for the same reasons, try to play nicely with the. */
+#ifndef isascii
+inline int isascii(int c) { return !(c & ~0x7F); }
+#define isascii isascii
+#endif
+#endif
+
 /* ++Autogenerated -- start of section automatically generated from Scintilla.iface */
 #define INVALID_POSITION -1
 #define SCI_START 2000