Use fseeko and ftello on BSDs

[liz-desartiges]

fseek64 seems to be specific to glibc and doesn't work an other unix platforms.
(musl and ulibc support it for glibc compatibility)

[liz-desartiges]

I would recommend using _FILE_OFFSET_BITS 64 macro instead of adding all those define, but it seams that you don't use large file for 32bits systems (on linux)

see : https://ftp.gnu.org/old-gnu/Manuals/glibc-2.2.3/html_node/libc_13.html for explanations

[liz-desartiges]

resulting in those changes instead

diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index d32b2b3..052ed28 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -103,14 +103,8 @@ distribution.
 #if defined(_WIN64)
 	#define TIXML_FSEEK _fseeki64
 	#define TIXML_FTELL _ftelli64
-#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
-	|| defined(__NetBSD__) || defined(__DragonFly__) || defined(__ANDROID__)
-	#define TIXML_FSEEK fseeko
-	#define TIXML_FTELL ftello
-#elif defined(__unix__) && defined(__x86_64__)
-	#define TIXML_FSEEK fseeko64
-	#define TIXML_FTELL ftello64
-#else
+#elif defined(__unix__)
+	#define _FILE_OFFSET_BITS 64
 	#define TIXML_FSEEK fseek
 	#define TIXML_FTELL ftell
 #endif

[liz-desartiges]

This macro should only be selected if the system provides mechanisms for handling large files. On 64 bit systems this macro has no effect since the *64 functions are identical to the normal functions.
this makes me think it is unnecessary in the first place to use the *64 variant for x86_64 versions