Re: [PATCH v2 08/11] cmake: added checks for struct stat and libiconv

> From: Sibi Siddharthan <sibisiddharthan.github@gmail.com>
> 
> The CMake script now checks whether st_blocks is a member of struct stat
> and set the compile definition NO_ST_BLOCKS_IN_STRUCT_STAT accordingly.
> 
> The check for whether ICONV_OMITS_BOM is also added as requested by Danh.

> Signed-off-by: Sibi Siddharthan <sibisiddharthan.github@gmail.com>
> ---
>  CMakeLists.txt | 59 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 57 insertions(+), 2 deletions(-)
> 
> diff --git a/CMakeLists.txt b/CMakeLists.txt
> index 4353080b708..975791c8b89 100644
> --- a/CMakeLists.txt
> +++ b/CMakeLists.txt
> @@ -22,6 +22,7 @@ project(git
>  include(CheckTypeSize)
>  include(CheckCSourceRuns)
>  include(CheckCSourceCompiles)
> +include(CheckCSourceRuns)
>  include(CheckIncludeFile)
>  include(CheckFunctionExists)
>  include(CheckSymbolExists)
> @@ -128,7 +129,7 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
>  	include_directories(compat/win32)
>  	add_compile_definitions(HAVE_ALLOCA_H NO_POSIX_GOODIES NATIVE_CRLF NO_UNIX_SOCKETS WIN32
>  				_CONSOLE DETECT_MSYS_TTY STRIP_EXTENSION=".exe"  NO_SYMLINK_HEAD UNRELIABLE_FSTAT
> -				NOGDI OBJECT_CREATION_MODE=1 __USE_MINGW_ANSI_STDIO=0 NO_ST_BLOCKS_IN_STRUCT_STAT
> +				NOGDI OBJECT_CREATION_MODE=1 __USE_MINGW_ANSI_STDIO=0
>  				USE_NED_ALLOCATOR OVERRIDE_STRDUP MMAP_PREVENTS_DELETE USE_WIN32_MMAP
>  				UNICODE _UNICODE HAVE_WPGMPTR ENSURE_MSYSTEM_IS_SET)
>  	list(APPEND compat_SOURCES compat/mingw.c compat/winansi.c compat/win32/path-utils.c
> @@ -280,6 +281,11 @@ if(HAVE_CLOCK_MONOTONIC)
>  	add_compile_definitions(HAVE_CLOCK_MONOTONIC)
>  endif()
>  
> +#check for st_blocks in struct stat
> +check_struct_has_member("struct stat" st_blocks "sys/stat.h" STRUCT_STAT_HAS_ST_BLOCKS)
> +if(NOT STRUCT_STAT_HAS_ST_BLOCKS)
> +	add_compile_definitions(NO_ST_BLOCKS_IN_STRUCT_STAT)
> +endif()
>  
>  #compile checks
>  check_c_source_runs("
> @@ -344,7 +350,6 @@ if(NOT HAVE_REGEX)
>  	add_compile_definitions(NO_REGEX NO_MBSUPPORT GAWK)
>  endif()
>  
> -
>  check_c_source_compiles("
>  #include <stddef.h>
>  #include <sys/types.h>
> @@ -368,6 +373,56 @@ if(HAVE_BSD_SYSCTL)
>  	add_compile_definitions(HAVE_BSD_SYSCTL)
>  endif()
>  
> +set(CMAKE_REQUIRED_LIBRARIES ${Iconv_LIBRARIES})
> +set(CMAKE_REQUIRED_INCLUDES ${Iconv_INCLUDE_DIRS})
> +
> +check_c_source_compiles("
> +#include <iconv.h>
> +
> +extern size_t iconv(iconv_t cd,
> +		char **inbuf, size_t *inbytesleft,
> +		char **outbuf, size_t *outbytesleft);
> +
> +int main(){return 0;}"
> +HAVE_NEW_ICONV)
> +if(HAVE_NEW_ICONV)
> +	set(HAVE_OLD_ICONV 0)
> +else()
> +	set(HAVE_OLD_ICONV 1)
> +endif()
> +
> +check_c_source_runs("
> +#include <iconv.h>
> +#if ${HAVE_OLD_ICONV}
> +typedef const char *iconv_ibp;
> +#else
> +typedef char *iconv_ibp;
> +#endif
> +
> +int main()
> +{
> +	int v;
> +	iconv_t conv;
> +	char in[] = \"a\"; iconv_ibp pin = in;
> +	char out[20] = \"\"; char *pout = out;
> +	size_t isz = sizeof in;
> +	size_t osz = sizeof out;
> +
> +	conv = iconv_open(\"UTF-16\", \"UTF-8\");
> +	iconv(conv, &pin, &isz, &pout, &osz);
> +	iconv_close(conv);
> +	v = (unsigned char)(out[0]) + (unsigned char)(out[1]);
> +	return v != 0xfe + 0xff;
> +}"