[PATCH 2/4] configure: compile-time word size detection

[Aaron Carroll <aaronc@xxxxxxxxxxxxxxx>]

Signed-off-by: Aaron Carroll <aaronc@xxxxxxxxxxxxxxx>
---
 configure |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/configure b/configure
index 1fa9b63..84c6af2 100755
--- a/configure
+++ b/configure
@@ -348,16 +348,20 @@ echo
 # check for wordsize
 wordsize="0"
 cat > $TMPC <<EOF
-#include <stdio.h>
+#include <limits.h>
+#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 int main(void)
 {
-  unsigned int wsize = sizeof(long) * 8;
-  printf("%d\n", wsize);
+  BUILD_BUG_ON(sizeof(long)*CHAR_BIT != WORDSIZE);
   return 0;
 }
 EOF
-if compile_prog "" "" "wordsize"; then
-  wordsize=`$TMPE`
+if compile_prog "-DWORDSIZE=32" "" "wordsize"; then
+  wordsize="32"
+elif compile_prog "-DWORDSIZE=64" "" "wordsize"; then
+  wordsize="64"
+else
+  fatal "Unknown wordsize"
 fi
 echo "Wordsize                      $wordsize"
 
-- 
1.7.0.4

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