Merge pull request #7874 from mpsuzuki/fix-posix-date

POSIX does not request "date" command to support "-R" option.

Author: douzzer

configure.ac

@@ -69,7 +69,7 @@ AS_IF([ test -n "$CFLAG_VISIBILITY" ], [
        AM_CFLAGS="$AM_CFLAGS $CFLAG_VISIBILITY"
        ])
 
-WOLFSSL_BUILD_DATE=$(date -R)
+WOLFSSL_BUILD_DATE=$(LC_TIME=C date +"%a, %d %b %Y %T %z")
 AC_SUBST([WOLFSSL_BUILD_DATE])