config.mak.uname: add sysinfo() configuration for cygwin

Although sysinfo() is a 'Linux only' function, cygwin provides an
implementation which appears to be functional. The assumption that
this function is Linux only is reflected in the way the HAVE_SYSINFO
build variable is handled by the Makefile and config.mak.uname.

Rework the setting of HAVE_SYSINFO in the Linux section of the system
specific config file, along with the corresponding setting of the
BASIC_CFLAGS in the Makefile. Add the setting of HAVE_SYSINFO to the
cygwin section of 'config.mak.uname'. While here, add a test for the
sysinfo() function to the autoconf build system.

Signed-off-by: Ramsay Jones <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ramsay-jones

Makefile

@@ -2168,6 +2168,10 @@ ifdef HAVE_SYNC_FILE_RANGE
 	BASIC_CFLAGS += -DHAVE_SYNC_FILE_RANGE
 endif
 
+ifdef HAVE_SYSINFO
+	BASIC_CFLAGS += -DHAVE_SYSINFO
+endif
+
 ifdef HAVE_BSD_SYSCTL
 	BASIC_CFLAGS += -DHAVE_BSD_SYSCTL
 endif

config.mak.uname

@@ -58,7 +58,7 @@ ifeq ($(uname_S),Linux)
 	HAVE_SYNC_FILE_RANGE = YesPlease
 	HAVE_GETDELIM = YesPlease
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
-	BASIC_CFLAGS += -DHAVE_SYSINFO
+	HAVE_SYSINFO = YesPlease
 	PROCFS_EXECUTABLE_PATH = /proc/self/exe
 	HAVE_PLATFORM_PROCINFO = YesPlease
 	COMPAT_OBJS += compat/linux/procinfo.o
@@ -253,6 +253,7 @@ ifeq ($(uname_O),Cygwin)
 	HAVE_GETDELIM = YesPlease
 	HAVE_CLOCK_GETTIME = YesPlease
 	HAVE_CLOCK_MONOTONIC = YesPlease
+	HAVE_SYSINFO = YesPlease
 	HAVE_ALLOCA_H = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes

configure.ac

@@ -1066,6 +1066,14 @@ AC_CHECK_LIB([iconv], [locale_charset],
        [AC_CHECK_LIB([charset], [locale_charset],
                      [CHARSET_LIB=-lcharset])])
 GIT_CONF_SUBST([CHARSET_LIB])
+
+#
+# Define HAVE_SYSINFO=YesPlease if sysinfo is available.
+GIT_CHECK_FUNC(sysinfo,
+	[HAVE_SYSINFO=YesPlease],
+	[HAVE_SYSINFO=])
+GIT_CONF_SUBST([HAVE_SYSINFO])
+
 #
 # Define HAVE_CLOCK_GETTIME=YesPlease if clock_gettime is available.
 GIT_CHECK_FUNC(clock_gettime,