Use memfd_create() to allocate the temporary SHM backing file in memory, and set the size with posix_fallocate(), which will return an error on insufficient space vs ftruncate(), which will silently succeed and allow a SIGBUS error to occur if the unbacked memory is accessed.
Additionally, make the legacy path more robust by unlinking the temp file, so it won't persist after close, and unmapping the shared memory buffer.
(cherry picked from commit 9bdb992925)
- check libiconv with a linkage test with iconv.h included
- check libc iconv with a linkage test with iconv.h included
and LIBICONV_PLUG defined (in case libiconv header is in
include path)
- add new configuration option to prefer iconv from libiconv,
if available, over the libc version, defaults to disabled:
SDL_LIBICONV for cmake, --enable-libiconv for autotools.
- change FreeBSD specific LIBICONV_PLUG define in SDL_iconv.c
to configuration result.
This fixes the following errors when a dll attempts to link to a shared SDL2::SDL2:
m.c.obj : error LNK2019: unresolved external symbol __imp___acrt_iob_func referenced in function printf
m.c.obj : error LNK2019: unresolved external symbol __imp___stdio_common_vfprintf referenced in function _vfprintf_l
MSVCRTD.lib(init.obj) : error LNK2019: unresolved external symbol _CrtDbgReport referenced in function _CRT_RTC_INIT
MSVCRTD.lib(init.obj) : error LNK2019: unresolved external symbol _CrtDbgReportW referenced in function _CRT_RTC_INITW
MSVCRTD.lib(error.obj) : error LNK2019: unresolved external symbol strcpy_s referenced in function "void __cdecl _RTC_StackFailure(void *,char const *)" (?_RTC_StackFailure@@YAXPEAXPEBD@Z)
MSVCRTD.lib(error.obj) : error LNK2019: unresolved external symbol strcat_s referenced in function "void __cdecl _RTC_StackFailure(void *,char const *)" (?_RTC_StackFailure@@YAXPEAXPEBD@Z)
MSVCRTD.lib(error.obj) : error LNK2019: unresolved external symbol __stdio_common_vsprintf_s referenced in function _vsprintf_s_l
MSVCRTD.lib(error.obj) : error LNK2001: unresolved external symbol __C_specific_handler_noexcept
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol _wmakepath_s referenced in function "int __cdecl GetPdbDllPathFromFilePath(wchar_t const *,wchar_t *,unsigned __int64)" (?GetPdbDllPathFromFilePath@@YAHPEB_WPEA_W_K@Z)
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol _wsplitpath_s referenced in function "int __cdecl GetPdbDllPathFromFilePath(wchar_t const *,wchar_t *,unsigned __int64)" (?GetPdbDllPathFromFilePath@@YAHPEB_WPEA_W_K@Z)
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol wcscpy_s referenced in function "int __cdecl GetPdbDllPathFromFilePath(wchar_t const *,wchar_t *,unsigned __int64)" (?GetPdbDllPathFromFilePath@@YAHPEB_WPEA_W_K@Z)
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol __vcrt_GetModuleFileNameW referenced in function "struct HINSTANCE__ * __cdecl GetPdbDll(void)" (?GetPdbDll@@YAPEAUHINSTANCE__@@XZ)
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol __vcrt_GetModuleHandleW referenced in function "struct HINSTANCE__ * __cdecl GetPdbDll(void)" (?GetPdbDll@@YAPEAUHINSTANCE__@@XZ)
MSVCRTD.lib(pdblkup.obj) : error LNK2019: unresolved external symbol __vcrt_LoadLibraryExW referenced in function "struct HINSTANCE__ * __cdecl GetPdbDll(void)" (?GetPdbDll@@YAPEAUHINSTANCE__@@XZ)
This fixes the following warning when configuring with CMake 3.27+:
```
CMake Deprecation Warning at CMakeLists.txt:3190 (cmake_minimum_required):
Compatibility with CMake < 3.5 will be removed from a future version of
CMake.
Update the VERSION argument <min> value or use a ...<max> suffix to tell
CMake that the project does not need compatibility with older versions.
```
The /Gs argument controls the number of bytes that local variables
can occupy before a stack probe is initiated.
By setting it to a huge value, no calls to __chkstk are inserted.
This change is needed for the classic Intel C compiler to build SDL
with -DSDL_LIBC=OFF.
