When checking if the architecture supports the %time register instruction, do not force -mcpu to v9 while doing so. Otherwise it's like "let's see if this v9 instruction exists when I force the compiler to think I'm using v9", which is non-sensical. Signed-off-by: Fabrice Fontaine diff -Naurp ./snort-2.9.11.1-orig/configure.in snort-2.9.11.1/configure.in --- ./snort-2.9.11.1-orig/configure.in 2018-05-10 12:20:19.253510678 +0200 +++ snort-2.9.11.1/configure.in 2018-05-10 12:40:18.547584998 +0200 @@ -942,8 +942,6 @@ fi # check for sparc %time register if eval "echo $host_cpu|grep -i sparc >/dev/null"; then - OLD_CFLAGS="$CFLAGS" - CFLAGS="$CFLAGS -mcpu=v9 " AC_MSG_CHECKING([for sparc %time register]) AC_RUN_IFELSE( [AC_LANG_PROGRAM( @@ -957,8 +955,6 @@ if eval "echo $host_cpu|grep -i sparc >/ AC_MSG_RESULT($sparcv9) if test "x$sparcv9" = "xyes"; then AC_DEFINE([SPARCV9],[1],[For sparc v9 with %time register]) - else - CFLAGS="$OLD_CFLAGS" fi fi