Change RAM check on Mac from sysctlbyname() to sysctl()

For an unknown reason, the RAM size returned by sysctlbyname() just up and went
nuts.  Switched to the more basic sysctl(), with all of the requisite changes
in the autotools code and program-wide definition file.  The results returned
by sysctl() seem to work.

	modified:   config.h.in
	modified:   configure.ac
	modified:   src/init.c
	modified:   src/sd_defs.h

config.h.in

@@ -179,8 +179,8 @@
 /* Define to 1 if you have the `strtol' function. */
 #undef HAVE_STRTOL
 
-/* Define to 1 if you have the `sysctlbyname' function. */
-#undef HAVE_SYSCTLBYNAME
+/* Define to 1 if you have the `sysctl' function. */
+#undef HAVE_SYSCTL
 
 /* Define to 1 if you have the `sysinfo' function. */
 #undef HAVE_SYSINFO

configure.ac

@@ -60,7 +60,7 @@ AC_CHECK_TYPES([socklen_t], [], [], [#include <sys/socket.h>])
 dnl ScopeDesign requirements
 AC_FUNC_MALLOC
 AC_CHECK_FUNCS([sqrt strdup])
-AC_CHECK_FUNCS([sysinfo sysctlbyname])
+AC_CHECK_FUNCS([sysinfo sysctl])
 
 
 dnl LIBARGTABLE requirements

src/init.c

@@ -53,13 +53,17 @@ int init_get_sysinfo(void){
   SYS_RAM = (double)s.totalram / 1024. / 1024.;  // in MB
 
 #elif HAVE__MAC
-  size_t size;
-  unsigned long long memsize;
-  sysctlbyname("HW_MEMSIZE", &memsize, &size, NULL, 0);
-  SYS_RAM = (double)memsize / 1024. / 1024.;   // In MB
+  int mib[2];
+  int64_t physical_memory;
+  size_t length;
+  mib[0] = CTL_HW;
+  mib[1] = HW_MEMSIZE;
+  length = sizeof(int64_t);
+  sysctl(mib, 2, &physical_memory, &length, NULL, 0);
+  SYS_RAM = (double)physical_memory / 1024. / 1024.;   // In MB
 
 #else
-  SYS_RAM = 0;
+  SYS_RAM = 0.;
 
 #endif
 

src/sd_defs.h

@@ -36,7 +36,7 @@
 # define HAVE__MAC   0
 # define HAVE__OTHER 0
 # define SD_SYS      50  // Linux
-#elif HAVE_SYSCTLBYNAME
+#elif HAVE_SYSCTL
 # define HAVE__LINUX 0
 # define HAVE__MAC   1
 # define HAVE__OTHER 0