-std=c99 prevents library build on MinGW

[ghost]

I found that there is used by default GCC option -std=c99 and this option causes automatic definition of __STRICT_ANSI__ macro.
Because in MinGW some typedefs are protected by using this macro then they are not visible and library cannot be compiled i.e.:
#ifndef __STRICT_ANSI__
typedef __int64 off64_t;
#endif /* __STRICT_ANSI__ */

I try to define C_FLAGS in CMake configuration but user C_FLAGS is put before predefined one and then I cannot override them.
After I changed CMAKE_C_FLAGS in the CMakeLists.txt to:
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
then everything build without problems.

cmake 5.5.2
mingw32-gcc 3.9.3.-1

$ mingw32-make cbor
[ 7%] Building C object src/CMakeFiles/cbor.dir/cbor.c.obj
In file included from c:\mingw\include\unistd.h:36:0,
from C:\tmp\libcbor-0.4.0\src\cbor.c:245:
c:\mingw\include\io.h:301:14: error: unknown type name 'off64_t'
__CRT_INLINE off64_t lseek64 (int, off64_t, int);
^
c:\mingw\include\io.h:301:36: error: unknown type name 'off64_t'
__CRT_INLINE off64_t lseek64 (int, off64_t, int);
^
c:\mingw\include\io.h:302:14: error: unknown type name 'off64_t'
__CRT_INLINE off64_t lseek64 (int fd, off64_t offset, int whence) {
^
c:\mingw\include\io.h:302:39: error: unknown type name 'off64_t'
__CRT_INLINE off64_t lseek64 (int fd, off64_t offset, int whence) {
^
In file included from C:\tmp\libcbor-0.4.0\src\cbor.c:245:0:
c:\mingw\include\unistd.h:65:20: error: unknown type name 'off_t'
int ftruncate(int, off_t);
^
src\CMakeFiles\cbor.dir\build.make:62: recipe for target 'src/CMakeFiles/cbor.dir/cbor.c.obj' failed
mingw32-make[3]: *** [src/CMakeFiles/cbor.dir/cbor.c.obj] Error 1
CMakeFiles\Makefile2:1037: recipe for target 'src/CMakeFiles/cbor.dir/all' failed
mingw32-make[2]: *** [src/CMakeFiles/cbor.dir/all] Error 2
CMakeFiles\Makefile2:1049: recipe for target 'src/CMakeFiles/cbor.dir/rule' failed
mingw32-make[1]: *** [src/CMakeFiles/cbor.dir/rule] Error 2
Makefile:571: recipe for target 'cbor' failed
mingw32-make: *** [cbor] Error 2

[PJK]

Hi, thanks for reporting, will be fixed in #45